Migrate Cloud Print utility messages to Mojo

These are the last remaining legacy IPC messages sent to or from any
utility process.

Bug: 993189
Change-Id: If231f7eaa9986deced8149a9095b31007945ab50
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2953763
Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Ken Rockot <rockot@google.com>
Cr-Commit-Position: refs/heads/master@{#891777}

chrome/common/BUILD.gn

@@ -395,7 +395,7 @@ static_library("common") {
       }
       if (is_win) {
         sources += [
-          "chrome_utility_printing_messages.h",
+          "chrome_utility_printing_param_traits_macros.h",
           "service_process_util_win.cc",
         ]
 
@@ -793,3 +793,25 @@ mojom("offline_page_auto_fetcher_mojom") {
   sources = [ "offline_page_auto_fetcher.mojom" ]
   public_deps = [ "//url/mojom:url_mojom_gurl" ]
 }
+
+if (enable_basic_printing && is_win) {
+  mojom("cloud_print_utility_mojom") {
+    sources = [ "cloud_print_utility.mojom" ]
+    cpp_typemaps = [
+      {
+        types = [
+          {
+            mojom = "chrome.mojom.PrinterCapsAndDefaults"
+            cpp = "::printing::PrinterCapsAndDefaults"
+          },
+          {
+            mojom = "chrome.mojom.PrinterSemanticCapsAndDefaults"
+            cpp = "::printing::PrinterSemanticCapsAndDefaults"
+          },
+        ]
+        traits_headers = [ "chrome_utility_printing_param_traits_macros.h" ]
+        traits_public_deps = [ ":common" ]
+      },
+    ]
+  }
+}

chrome/common/chrome_utility_printing_messages.h

@@ -1,105 +0,0 @@
-// Copyright 2014 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef CHROME_COMMON_CHROME_UTILITY_PRINTING_MESSAGES_H_
-#define CHROME_COMMON_CHROME_UTILITY_PRINTING_MESSAGES_H_
-
-#include <string>
-
-#include "build/build_config.h"
-#include "ipc/ipc_message_macros.h"
-#include "ipc/ipc_message_start.h"
-#include "ipc/ipc_param_traits.h"
-#include "printing/backend/print_backend.h"
-#include "printing/buildflags/buildflags.h"
-#include "printing/mojom/print.mojom.h"
-
-#define IPC_MESSAGE_START ChromeUtilityPrintingMsgStart
-
-#if defined(OS_WIN) && BUILDFLAG(ENABLE_PRINT_PREVIEW)
-// Preview and Cloud Print messages.
-IPC_STRUCT_TRAITS_BEGIN(printing::PrinterCapsAndDefaults)
-  IPC_STRUCT_TRAITS_MEMBER(printer_capabilities)
-  IPC_STRUCT_TRAITS_MEMBER(caps_mime_type)
-  IPC_STRUCT_TRAITS_MEMBER(printer_defaults)
-  IPC_STRUCT_TRAITS_MEMBER(defaults_mime_type)
-IPC_STRUCT_TRAITS_END()
-
-IPC_ENUM_TRAITS_MAX_VALUE(printing::mojom::ColorModel,
-                          printing::mojom::ColorModel::kColorModelLast)
-
-IPC_STRUCT_TRAITS_BEGIN(printing::PrinterSemanticCapsAndDefaults::Paper)
-  IPC_STRUCT_TRAITS_MEMBER(display_name)
-  IPC_STRUCT_TRAITS_MEMBER(vendor_id)
-  IPC_STRUCT_TRAITS_MEMBER(size_um)
-IPC_STRUCT_TRAITS_END()
-
-IPC_ENUM_TRAITS_MIN_MAX_VALUE(printing::mojom::DuplexMode,
-                              printing::mojom::DuplexMode::kUnknownDuplexMode,
-                              printing::mojom::DuplexMode::kShortEdge)
-
-IPC_STRUCT_TRAITS_BEGIN(printing::PrinterSemanticCapsAndDefaults)
-  IPC_STRUCT_TRAITS_MEMBER(collate_capable)
-  IPC_STRUCT_TRAITS_MEMBER(collate_default)
-  IPC_STRUCT_TRAITS_MEMBER(copies_max)
-  IPC_STRUCT_TRAITS_MEMBER(duplex_modes)
-  IPC_STRUCT_TRAITS_MEMBER(duplex_default)
-  IPC_STRUCT_TRAITS_MEMBER(color_changeable)
-  IPC_STRUCT_TRAITS_MEMBER(color_default)
-  IPC_STRUCT_TRAITS_MEMBER(color_model)
-  IPC_STRUCT_TRAITS_MEMBER(bw_model)
-  IPC_STRUCT_TRAITS_MEMBER(papers)
-  IPC_STRUCT_TRAITS_MEMBER(default_paper)
-  IPC_STRUCT_TRAITS_MEMBER(dpis)
-  IPC_STRUCT_TRAITS_MEMBER(default_dpi)
-IPC_STRUCT_TRAITS_END()
-
-//------------------------------------------------------------------------------
-// Utility process messages:
-// These are messages from the browser to the utility process.
-
-// Tells the utility process to get capabilities and defaults for the specified
-// printer. Used on Windows to isolate the service process from printer driver
-// crashes by executing this in a separate process. This does not run in a
-// sandbox.
-IPC_MESSAGE_CONTROL1(ChromeUtilityMsg_GetPrinterCapsAndDefaults,
-                     std::string /* printer name */)
-
-// Tells the utility process to get capabilities and defaults for the specified
-// printer. Used on Windows to isolate the service process from printer driver
-// crashes by executing this in a separate process. This does not run in a
-// sandbox. Returns result as printing::PrinterSemanticCapsAndDefaults.
-IPC_MESSAGE_CONTROL1(ChromeUtilityMsg_GetPrinterSemanticCapsAndDefaults,
-                     std::string /* printer name */)
-
-//------------------------------------------------------------------------------
-// Utility process host messages:
-// These are messages from the utility process to the browser.
-
-// Reply when the utility process has succeeded in obtaining the printer
-// capabilities and defaults.
-IPC_MESSAGE_CONTROL2(ChromeUtilityHostMsg_GetPrinterCapsAndDefaults_Succeeded,
-                     std::string /* printer name */,
-                     printing::PrinterCapsAndDefaults)
-
-// Reply when the utility process has succeeded in obtaining the printer
-// semantic capabilities and defaults.
-IPC_MESSAGE_CONTROL2(
-    ChromeUtilityHostMsg_GetPrinterSemanticCapsAndDefaults_Succeeded,
-    std::string /* printer name */,
-    printing::PrinterSemanticCapsAndDefaults)
-
-// Reply when the utility process has failed to obtain the printer
-// capabilities and defaults.
-IPC_MESSAGE_CONTROL1(ChromeUtilityHostMsg_GetPrinterCapsAndDefaults_Failed,
-                     std::string /* printer name */)
-
-// Reply when the utility process has failed to obtain the printer
-// semantic capabilities and defaults.
-IPC_MESSAGE_CONTROL1(
-  ChromeUtilityHostMsg_GetPrinterSemanticCapsAndDefaults_Failed,
-  std::string /* printer name */)
-#endif  // defined(OS_WIN) && BUILDFLAG(ENABLE_PRINT_PREVIEW)
-
-#endif  // CHROME_COMMON_CHROME_UTILITY_PRINTING_MESSAGES_H_

chrome/common/chrome_utility_printing_param_traits_macros.h

@@ -0,0 +1,56 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_COMMON_CHROME_UTILITY_PRINTING_PARAM_TRAITS_MACROS_H_
+#define CHROME_COMMON_CHROME_UTILITY_PRINTING_PARAM_TRAITS_MACROS_H_
+
+#include "build/build_config.h"
+#include "ipc/ipc_message_macros.h"
+#include "ipc/ipc_message_start.h"
+#include "ipc/ipc_param_traits.h"
+#include "printing/backend/print_backend.h"
+#include "printing/buildflags/buildflags.h"
+#include "printing/mojom/print.mojom.h"
+
+#if defined(OS_WIN) && BUILDFLAG(ENABLE_PRINT_PREVIEW)
+// Preview and Cloud Print messages.
+IPC_STRUCT_TRAITS_BEGIN(printing::PrinterCapsAndDefaults)
+  IPC_STRUCT_TRAITS_MEMBER(printer_capabilities)
+  IPC_STRUCT_TRAITS_MEMBER(caps_mime_type)
+  IPC_STRUCT_TRAITS_MEMBER(printer_defaults)
+  IPC_STRUCT_TRAITS_MEMBER(defaults_mime_type)
+IPC_STRUCT_TRAITS_END()
+
+IPC_ENUM_TRAITS_MAX_VALUE(printing::mojom::ColorModel,
+                          printing::mojom::ColorModel::kColorModelLast)
+
+IPC_STRUCT_TRAITS_BEGIN(printing::PrinterSemanticCapsAndDefaults::Paper)
+  IPC_STRUCT_TRAITS_MEMBER(display_name)
+  IPC_STRUCT_TRAITS_MEMBER(vendor_id)
+  IPC_STRUCT_TRAITS_MEMBER(size_um)
+IPC_STRUCT_TRAITS_END()
+
+IPC_ENUM_TRAITS_MIN_MAX_VALUE(printing::mojom::DuplexMode,
+                              printing::mojom::DuplexMode::kUnknownDuplexMode,
+                              printing::mojom::DuplexMode::kShortEdge)
+
+IPC_STRUCT_TRAITS_BEGIN(printing::PrinterSemanticCapsAndDefaults)
+  IPC_STRUCT_TRAITS_MEMBER(collate_capable)
+  IPC_STRUCT_TRAITS_MEMBER(collate_default)
+  IPC_STRUCT_TRAITS_MEMBER(copies_max)
+  IPC_STRUCT_TRAITS_MEMBER(duplex_modes)
+  IPC_STRUCT_TRAITS_MEMBER(duplex_default)
+  IPC_STRUCT_TRAITS_MEMBER(color_changeable)
+  IPC_STRUCT_TRAITS_MEMBER(color_default)
+  IPC_STRUCT_TRAITS_MEMBER(color_model)
+  IPC_STRUCT_TRAITS_MEMBER(bw_model)
+  IPC_STRUCT_TRAITS_MEMBER(papers)
+  IPC_STRUCT_TRAITS_MEMBER(default_paper)
+  IPC_STRUCT_TRAITS_MEMBER(dpis)
+  IPC_STRUCT_TRAITS_MEMBER(default_dpi)
+IPC_STRUCT_TRAITS_END()
+
+#endif  // defined(OS_WIN) && BUILDFLAG(ENABLE_PRINT_PREVIEW)
+
+#endif  // CHROME_COMMON_CHROME_UTILITY_PRINTING_PARAM_TRAITS_MACROS_H_

chrome/common/cloud_print_utility.mojom

@@ -0,0 +1,29 @@
+// Copyright 2021 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+module chrome.mojom;
+
+// Interface implemented by the unsandboxed Cloud Print utility process (see
+// src/chrome/utility/printing_handler.cc) and called by the Cloud Print service
+// process, which is a special Windows service process run by the deprecated
+// Cloud Print Connector tool. The purpose of the utility process is to isolate
+// printer driver crashes from the service process.
+interface CloudPrintUtility {
+  // Retrieves capabilities and defaults for the specified printer. Returns null
+  // on failure.
+  GetPrinterCapsAndDefaults(string printer_name)
+      => (PrinterCapsAndDefaults? caps_and_defaults);
+
+  // Retrieves capabilities and defaults for the specified printer. Returns null
+  // on failure.
+  GetPrinterSemanticCapsAndDefaults(string printer_name)
+      => (PrinterSemanticCapsAndDefaults? caps_and_defaults);
+};
+
+[Native]
+struct PrinterCapsAndDefaults;
+
+[Native]
+struct PrinterSemanticCapsAndDefaults;
+

chrome/common/common_message_generator.h

@@ -14,11 +14,11 @@
 #include "printing/buildflags/buildflags.h"
 
 #if BUILDFLAG(ENABLE_PRINTING)
-#undef CHROME_COMMON_CHROME_UTILITY_PRINTING_MESSAGES_H_
-#include "chrome/common/chrome_utility_printing_messages.h"
-#ifndef CHROME_COMMON_CHROME_UTILITY_PRINTING_MESSAGES_H_
+#undef CHROME_COMMON_CHROME_UTILITY_PRINTING_PARAM_TRAITS_MACROS_H_
+#include "chrome/common/chrome_utility_printing_param_traits_macros.h"
+#ifndef CHROME_COMMON_CHROME_UTILITY_PRINTING_PARAM_TRAITS_MACROS_H_
 #error \
-    "Failed to include header chrome/common/chrome_utility_printing_messages.h"
+    "Failed to include header chrome/common/chrome_utility_printing_param_traits_macros.h"
 #endif
 #endif
 

chrome/service/BUILD.gn

@@ -95,6 +95,9 @@ static_library("service") {
       "service_utility_process_host.h",
       "service_utility_process_host_receiver_bindings.cc",
     ]
-    deps += [ "//sandbox/win:sandbox" ]
+    deps += [
+      "//chrome/common:cloud_print_utility_mojom",
+      "//sandbox/win:sandbox",
+    ]
   }
 }

chrome/service/service_utility_process_host.cc

@@ -28,7 +28,7 @@
 #include "base/win/win_util.h"
 #include "build/build_config.h"
 #include "chrome/common/chrome_switches.h"
-#include "chrome/common/chrome_utility_printing_messages.h"
+#include "chrome/common/cloud_print_utility.mojom.h"
 #include "chrome/services/printing/public/mojom/pdf_to_emf_converter.mojom.h"
 #include "content/public/common/child_process_host.h"
 #include "content/public/common/content_switches.h"
@@ -221,6 +221,8 @@ ServiceUtilityProcessHost::ServiceUtilityProcessHost(
       waiting_for_reply_(false) {
   child_process_host_ =
       ChildProcessHost::Create(this, ChildProcessHost::IpcMode::kNormal);
+  child_process_host_->BindReceiver(
+      cloud_print_utility_remote_.BindNewPipeAndPassReceiver());
 }
 
 ServiceUtilityProcessHost::~ServiceUtilityProcessHost() {
@@ -267,7 +269,11 @@ bool ServiceUtilityProcessHost::StartGetPrinterCapsAndDefaults(
     return false;
   DCHECK(!waiting_for_reply_);
   waiting_for_reply_ = true;
-  return Send(new ChromeUtilityMsg_GetPrinterCapsAndDefaults(printer_name));
+  cloud_print_utility_remote_->GetPrinterCapsAndDefaults(
+      printer_name,
+      base::BindOnce(&ServiceUtilityProcessHost::OnGetPrinterCapsAndDefaults,
+                     base::Unretained(this), printer_name));
+  return true;
 }
 
 bool ServiceUtilityProcessHost::StartGetPrinterSemanticCapsAndDefaults(
@@ -276,8 +282,12 @@ bool ServiceUtilityProcessHost::StartGetPrinterSemanticCapsAndDefaults(
     return false;
   DCHECK(!waiting_for_reply_);
   waiting_for_reply_ = true;
-  return Send(
-      new ChromeUtilityMsg_GetPrinterSemanticCapsAndDefaults(printer_name));
+  cloud_print_utility_remote_->GetPrinterSemanticCapsAndDefaults(
+      printer_name,
+      base::BindOnce(
+          &ServiceUtilityProcessHost::OnGetPrinterSemanticCapsAndDefaults,
+          base::Unretained(this), printer_name));
+  return true;
 }
 
 bool ServiceUtilityProcessHost::StartProcess(bool sandbox) {
@@ -287,10 +297,6 @@ bool ServiceUtilityProcessHost::StartProcess(bool sandbox) {
     return false;
   }
 
-  // NOTE: This call to |CreateChannelMojo()| requires a working
-  // ServiceManagerConnection to have already been established.
-  child_process_host_->CreateChannelMojo();
-
   base::CommandLine cmd_line(exe_path);
   cmd_line.AppendSwitchASCII(switches::kProcessType, switches::kUtilityProcess);
   cmd_line.AppendSwitch(switches::kLang);
@@ -357,13 +363,6 @@ bool ServiceUtilityProcessHost::Launch(base::CommandLine* cmd_line,
   return true;
 }
 
-bool ServiceUtilityProcessHost::Send(IPC::Message* msg) {
-  if (child_process_host_)
-    return child_process_host_->Send(msg);
-  delete msg;
-  return false;
-}
-
 base::FilePath ServiceUtilityProcessHost::GetUtilityProcessCmd() {
   return ChildProcessHost::GetChildPath(ChildProcessHost::CHILD_NORMAL);
 }
@@ -381,22 +380,7 @@ void ServiceUtilityProcessHost::OnChildDisconnected() {
 }
 
 bool ServiceUtilityProcessHost::OnMessageReceived(const IPC::Message& message) {
-  bool handled = true;
-  IPC_BEGIN_MESSAGE_MAP(ServiceUtilityProcessHost, message)
-    IPC_MESSAGE_HANDLER(
-        ChromeUtilityHostMsg_GetPrinterCapsAndDefaults_Succeeded,
-        OnGetPrinterCapsAndDefaultsSucceeded)
-    IPC_MESSAGE_HANDLER(ChromeUtilityHostMsg_GetPrinterCapsAndDefaults_Failed,
-                        OnGetPrinterCapsAndDefaultsFailed)
-    IPC_MESSAGE_HANDLER(
-        ChromeUtilityHostMsg_GetPrinterSemanticCapsAndDefaults_Succeeded,
-        OnGetPrinterSemanticCapsAndDefaultsSucceeded)
-    IPC_MESSAGE_HANDLER(
-        ChromeUtilityHostMsg_GetPrinterSemanticCapsAndDefaults_Failed,
-        OnGetPrinterSemanticCapsAndDefaultsFailed)
-    IPC_MESSAGE_UNHANDLED(handled = false)
-  IPC_END_MESSAGE_MAP()
-  return handled;
+  return false;
 }
 
 const base::Process& ServiceUtilityProcessHost::GetProcess() {
@@ -448,52 +432,33 @@ void ServiceUtilityProcessHost::OnPDFToEmfFinished(bool success) {
   delete this;
 }
 
-void ServiceUtilityProcessHost::OnGetPrinterCapsAndDefaultsSucceeded(
+void ServiceUtilityProcessHost::OnGetPrinterCapsAndDefaults(
     const std::string& printer_name,
-    const printing::PrinterCapsAndDefaults& caps_and_defaults) {
+    const absl::optional<printing::PrinterCapsAndDefaults>& caps_and_defaults) {
   DCHECK(waiting_for_reply_);
   waiting_for_reply_ = false;
   client_task_runner_->PostTask(
       FROM_HERE,
-      base::BindOnce(&Client::OnGetPrinterCapsAndDefaults, client_.get(), true,
-                     printer_name, caps_and_defaults));
+      base::BindOnce(
+          &Client::OnGetPrinterCapsAndDefaults, client_.get(),
+          caps_and_defaults.has_value(), printer_name,
+          caps_and_defaults.value_or(printing::PrinterCapsAndDefaults())));
   // The child process disconnects itself and this host deletes itself via
   // OnChildDisconnected().
 }
 
-void ServiceUtilityProcessHost::OnGetPrinterSemanticCapsAndDefaultsSucceeded(
+void ServiceUtilityProcessHost::OnGetPrinterSemanticCapsAndDefaults(
     const std::string& printer_name,
-    const printing::PrinterSemanticCapsAndDefaults& caps_and_defaults) {
+    const absl::optional<printing::PrinterSemanticCapsAndDefaults>&
+        caps_and_defaults) {
   DCHECK(waiting_for_reply_);
   waiting_for_reply_ = false;
   client_task_runner_->PostTask(
       FROM_HERE,
       base::BindOnce(&Client::OnGetPrinterSemanticCapsAndDefaults,
-                     client_.get(), true, printer_name, caps_and_defaults));
-  // The child process disconnects itself and this host deletes itself via
-  // OnChildDisconnected().
-}
-
-void ServiceUtilityProcessHost::OnGetPrinterCapsAndDefaultsFailed(
-    const std::string& printer_name) {
-  DCHECK(waiting_for_reply_);
-  waiting_for_reply_ = false;
-  client_task_runner_->PostTask(
-      FROM_HERE,
-      base::BindOnce(&Client::OnGetPrinterCapsAndDefaults, client_.get(), false,
-                     printer_name, printing::PrinterCapsAndDefaults()));
-  // The child process disconnects itself and this host deletes itself via
-  // OnChildDisconnected().
-}
-
-void ServiceUtilityProcessHost::OnGetPrinterSemanticCapsAndDefaultsFailed(
-    const std::string& printer_name) {
-  DCHECK(waiting_for_reply_);
-  waiting_for_reply_ = false;
-  client_task_runner_->PostTask(
-      FROM_HERE, base::BindOnce(&Client::OnGetPrinterSemanticCapsAndDefaults,
-                                client_.get(), false, printer_name,
-                                printing::PrinterSemanticCapsAndDefaults()));
+                     client_.get(), caps_and_defaults.has_value(), printer_name,
+                     caps_and_defaults.value_or(
+                         printing::PrinterSemanticCapsAndDefaults())));
   // The child process disconnects itself and this host deletes itself via
   // OnChildDisconnected().
 }

chrome/service/service_utility_process_host.h

@@ -11,10 +11,12 @@
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
+#include "chrome/common/cloud_print_utility.mojom.h"
 #include "chrome/services/printing/public/mojom/pdf_to_emf_converter.mojom.h"
 #include "content/public/common/child_process_host_delegate.h"
-#include "ipc/ipc_platform_file.h"
 #include "mojo/public/cpp/bindings/pending_remote.h"
+#include "mojo/public/cpp/bindings/remote.h"
+#include "third_party/abseil-cpp/absl/types/optional.h"
 
 namespace base {
 class CommandLine;
@@ -112,8 +114,6 @@ class ServiceUtilityProcessHost : public content::ChildProcessHostDelegate {
   bool StartGetPrinterSemanticCapsAndDefaults(const std::string& printer_name);
 
  protected:
-  bool Send(IPC::Message* msg);
-
   // Allows this method to be overridden for tests.
   virtual base::FilePath GetUtilityProcessCmd();
 
@@ -143,19 +143,19 @@ class ServiceUtilityProcessHost : public content::ChildProcessHostDelegate {
       base::ReadOnlySharedMemoryRegion emf_region,
       float scale_factor);
 
-  // IPC Messages handlers:
-  void OnGetPrinterCapsAndDefaultsSucceeded(
+  // IPC response handlers:
+  void OnGetPrinterCapsAndDefaults(
       const std::string& printer_name,
-      const printing::PrinterCapsAndDefaults& caps_and_defaults);
-  void OnGetPrinterCapsAndDefaultsFailed(const std::string& printer_name);
-  void OnGetPrinterSemanticCapsAndDefaultsSucceeded(
+      const absl::optional<printing::PrinterCapsAndDefaults>&
+          caps_and_defaults);
+  void OnGetPrinterSemanticCapsAndDefaults(
       const std::string& printer_name,
-      const printing::PrinterSemanticCapsAndDefaults& caps_and_defaults);
-  void OnGetPrinterSemanticCapsAndDefaultsFailed(
-      const std::string& printer_name);
+      const absl::optional<printing::PrinterSemanticCapsAndDefaults>&
+          caps_and_defaults);
 
   std::unique_ptr<content::ChildProcessHost> child_process_host_;
   base::Process process_;
+  mojo::Remote<chrome::mojom::CloudPrintUtility> cloud_print_utility_remote_;
   // A pointer to our client interface, who will be informed of progress.
   scoped_refptr<Client> client_;
   scoped_refptr<base::SingleThreadTaskRunner> client_task_runner_;

chrome/utility/BUILD.gn

@@ -221,6 +221,7 @@ static_library("utility") {
         "printing_handler.cc",
         "printing_handler.h",
       ]
+      public_deps += [ "//chrome/common:cloud_print_utility_mojom" ]
     }
   }
 

chrome/utility/browser_exposed_utility_interfaces.cc

@@ -13,6 +13,25 @@
 #include "chrome/services/printing/pdf_to_emf_converter_factory.h"
 #endif
 
+#if BUILDFLAG(ENABLE_PRINT_PREVIEW) && defined(OS_WIN)
+#include "chrome/common/cloud_print_utility.mojom.h"
+#include "chrome/utility/printing_handler.h"
+#include "mojo/public/cpp/bindings/pending_receiver.h"
+#include "mojo/public/cpp/bindings/self_owned_receiver.h"
+#endif
+
+#if BUILDFLAG(ENABLE_PRINT_PREVIEW) && defined(OS_WIN)
+namespace {
+
+void BindCloudPrintUtility(
+    mojo::PendingReceiver<chrome::mojom::CloudPrintUtility> receiver) {
+  mojo::MakeSelfOwnedReceiver(std::make_unique<printing::PrintingHandler>(),
+                              std::move(receiver));
+}
+
+}  // namespace
+#endif
+
 void ExposeElevatedChromeUtilityInterfacesToBrowser(mojo::BinderMap* binders) {
 #if BUILDFLAG(ENABLE_PRINTING) && defined(OS_WIN)
   // TODO(crbug.com/798782): remove when the Cloud print chrome/service is
@@ -20,4 +39,7 @@ void ExposeElevatedChromeUtilityInterfacesToBrowser(mojo::BinderMap* binders) {
   binders->Add(base::BindRepeating(printing::PdfToEmfConverterFactory::Create),
                base::ThreadTaskRunnerHandle::Get());
 #endif
+#if BUILDFLAG(ENABLE_PRINT_PREVIEW) && defined(OS_WIN)
+  binders->Add(base::BindRepeating(&BindCloudPrintUtility));
+#endif
 }

chrome/utility/chrome_content_utility_client.cc

@@ -34,9 +34,6 @@ base::LazyInstance<ChromeContentUtilityClient::NetworkBinderCreationCallback>::
 
 ChromeContentUtilityClient::ChromeContentUtilityClient()
     : utility_process_running_elevated_(false) {
-#if BUILDFLAG(ENABLE_PRINT_PREVIEW) && defined(OS_WIN)
-  printing_handler_ = std::make_unique<printing::PrintingHandler>();
-#endif
 }
 
 ChromeContentUtilityClient::~ChromeContentUtilityClient() = default;
@@ -59,18 +56,6 @@ void ChromeContentUtilityClient::ExposeInterfacesToBrowser(
     ExposeElevatedChromeUtilityInterfacesToBrowser(binders);
 }
 
-bool ChromeContentUtilityClient::OnMessageReceived(
-    const IPC::Message& message) {
-  if (utility_process_running_elevated_)
-    return false;
-
-#if BUILDFLAG(ENABLE_PRINT_PREVIEW) && defined(OS_WIN)
-  if (printing_handler_->OnMessageReceived(message))
-    return true;
-#endif
-  return false;
-}
-
 void ChromeContentUtilityClient::RegisterNetworkBinders(
     service_manager::BinderRegistry* registry) {
   if (g_network_binder_creation_callback.Get())

chrome/utility/chrome_content_utility_client.h

@@ -27,7 +27,6 @@ class ChromeContentUtilityClient : public content::ContentUtilityClient {
 
   // content::ContentUtilityClient:
   void ExposeInterfacesToBrowser(mojo::BinderMap* binders) override;
-  bool OnMessageReceived(const IPC::Message& message) override;
   void PostIOThreadCreated(
       base::SingleThreadTaskRunner* io_thread_task_runner) override;
   void RegisterNetworkBinders(

chrome/utility/printing_handler.cc

@@ -5,22 +5,17 @@
 #include "chrome/utility/printing_handler.h"
 
 #include "build/build_config.h"
-#include "chrome/common/chrome_utility_printing_messages.h"
 #include "components/crash/core/common/crash_keys.h"
 #include "content/public/utility/utility_thread.h"
-#include "ipc/ipc_message.h"
 #include "printing/backend/print_backend.h"
 #include "printing/buildflags/buildflags.h"
 #include "printing/mojom/print.mojom.h"
+#include "third_party/abseil-cpp/absl/types/optional.h"
 
 namespace printing {
 
 namespace {
 
-bool Send(IPC::Message* message) {
-  return content::UtilityThread::Get()->Send(message);
-}
-
 void ReleaseProcess() {
   content::UtilityThread::Get()->ReleaseProcess();
 }
@@ -31,20 +26,9 @@ PrintingHandler::PrintingHandler() = default;
 
 PrintingHandler::~PrintingHandler() = default;
 
-bool PrintingHandler::OnMessageReceived(const IPC::Message& message) {
-  bool handled = true;
-  IPC_BEGIN_MESSAGE_MAP(PrintingHandler, message)
-    IPC_MESSAGE_HANDLER(ChromeUtilityMsg_GetPrinterCapsAndDefaults,
-                        OnGetPrinterCapsAndDefaults)
-    IPC_MESSAGE_HANDLER(ChromeUtilityMsg_GetPrinterSemanticCapsAndDefaults,
-                        OnGetPrinterSemanticCapsAndDefaults)
-    IPC_MESSAGE_UNHANDLED(handled = false)
-  IPC_END_MESSAGE_MAP()
-  return handled;
-}
-
-void PrintingHandler::OnGetPrinterCapsAndDefaults(
-    const std::string& printer_name) {
+void PrintingHandler::GetPrinterCapsAndDefaults(
+    const std::string& printer_name,
+    GetPrinterCapsAndDefaultsCallback callback) {
   scoped_refptr<PrintBackend> print_backend =
       PrintBackend::CreateInstance(/*locale=*/std::string());
   PrinterCapsAndDefaults printer_info;
@@ -54,17 +38,16 @@ void PrintingHandler::OnGetPrinterCapsAndDefaults(
 
   if (print_backend->GetPrinterCapsAndDefaults(printer_name, &printer_info) ==
       mojom::ResultCode::kSuccess) {
-    Send(new ChromeUtilityHostMsg_GetPrinterCapsAndDefaults_Succeeded(
-        printer_name, printer_info));
+    std::move(callback).Run(printer_info);
   } else {
-    Send(new ChromeUtilityHostMsg_GetPrinterCapsAndDefaults_Failed(
-        printer_name));
+    std::move(callback).Run(absl::nullopt);
   }
   ReleaseProcess();
 }
 
-void PrintingHandler::OnGetPrinterSemanticCapsAndDefaults(
-    const std::string& printer_name) {
+void PrintingHandler::GetPrinterSemanticCapsAndDefaults(
+    const std::string& printer_name,
+    GetPrinterSemanticCapsAndDefaultsCallback callback) {
   scoped_refptr<PrintBackend> print_backend =
       PrintBackend::CreateInstance(/*locale=*/std::string());
   PrinterSemanticCapsAndDefaults printer_info;
@@ -74,11 +57,9 @@ void PrintingHandler::OnGetPrinterSemanticCapsAndDefaults(
 
   if (print_backend->GetPrinterSemanticCapsAndDefaults(
           printer_name, &printer_info) == mojom::ResultCode::kSuccess) {
-    Send(new ChromeUtilityHostMsg_GetPrinterSemanticCapsAndDefaults_Succeeded(
-        printer_name, printer_info));
+    std::move(callback).Run(printer_info);
   } else {
-    Send(new ChromeUtilityHostMsg_GetPrinterSemanticCapsAndDefaults_Failed(
-        printer_name));
+    std::move(callback).Run(absl::nullopt);
   }
   ReleaseProcess();
 }

chrome/utility/printing_handler.h

@@ -9,32 +9,31 @@
 
 #include "base/macros.h"
 #include "build/build_config.h"
+#include "chrome/common/cloud_print_utility.mojom.h"
 #include "printing/buildflags/buildflags.h"
 
 #if !defined(OS_WIN) || !BUILDFLAG(ENABLE_PRINT_PREVIEW)
 #error "Windows printing and print preview must be enabled"
 #endif
 
-namespace IPC {
-class Message;
-}
-
 namespace printing {
 
 // Dispatches IPCs for printing.
-class PrintingHandler {
+class PrintingHandler : public chrome::mojom::CloudPrintUtility {
  public:
   PrintingHandler();
-  ~PrintingHandler();
-
-  bool OnMessageReceived(const IPC::Message& message);
+  PrintingHandler(const PrintingHandler&) = delete;
+  PrintingHandler& operator=(const PrintingHandler&) = delete;
+  ~PrintingHandler() override;
 
  private:
-  // IPC message handlers.
-  void OnGetPrinterCapsAndDefaults(const std::string& printer_name);
-  void OnGetPrinterSemanticCapsAndDefaults(const std::string& printer_name);
-
-  DISALLOW_COPY_AND_ASSIGN(PrintingHandler);
+  // chrome::mojom::CloudPrintUtility:
+  void GetPrinterCapsAndDefaults(
+      const std::string& printer_name,
+      GetPrinterCapsAndDefaultsCallback callback) override;
+  void GetPrinterSemanticCapsAndDefaults(
+      const std::string& printer_name,
+      GetPrinterSemanticCapsAndDefaultsCallback callback) override;
 };
 
 }  // namespace printing

content/public/utility/content_utility_client.cc

@@ -6,10 +6,6 @@
 
 namespace content {
 
-bool ContentUtilityClient::OnMessageReceived(const IPC::Message& message) {
-  return false;
-}
-
 bool ContentUtilityClient::HandleServiceRequestDeprecated(
     const std::string& service_name,
     mojo::ScopedMessagePipeHandle service_pipe) {

content/public/utility/content_utility_client.h

@@ -13,10 +13,6 @@
 #include "mojo/public/cpp/bindings/generic_pending_receiver.h"
 #include "services/service_manager/public/cpp/binder_registry.h"
 
-namespace IPC {
-class Message;
-}
-
 namespace mojo {
 class BinderMap;
 class ServiceFactory;
@@ -32,9 +28,6 @@ class CONTENT_EXPORT ContentUtilityClient {
   // Notifies us that the UtilityThread has been created.
   virtual void UtilityThreadStarted() {}
 
-  // Allows the embedder to filter messages.
-  virtual bool OnMessageReceived(const IPC::Message& message);
-
   // Allows the embedder to register interface binders to handle interface
   // requests coming in from the browser process. These are requests that the
   // browser issues through the ChildProcessHost's BindReceiver() API on the

content/utility/utility_thread_impl.cc

@@ -252,10 +252,6 @@ void UtilityThreadImpl::Init() {
   service_factory_ = std::make_unique<UtilityServiceFactory>();
 }
 
-bool UtilityThreadImpl::OnControlMessageReceived(const IPC::Message& msg) {
-  return GetContentClient()->utility()->OnMessageReceived(msg);
-}
-
 void UtilityThreadImpl::RunServiceDeprecated(
     const std::string& service_name,
     mojo::ScopedMessagePipeHandle service_pipe) {

content/utility/utility_thread_impl.h

@@ -56,7 +56,6 @@ class UtilityThreadImpl : public UtilityThread,
   void Init();
 
   // ChildThreadImpl:
-  bool OnControlMessageReceived(const IPC::Message& msg) override;
   void RunServiceDeprecated(
       const std::string& service_name,
       mojo::ScopedMessagePipeHandle service_pipe) override;

ipc/ipc_message_start.h

@@ -23,7 +23,6 @@ enum IPCMessageStart {
   NaClHostMsgStart,
   EncryptedMediaMsgStart,
   GinJavaBridgeMsgStart,
-  ChromeUtilityPrintingMsgStart,
   ExtensionsGuestViewMsgStart,
   GuestViewMsgStart,
   MediaPlayerDelegateMsgStart,

ipc/trace_ipc_message.cc

@@ -53,9 +53,6 @@ void WriteIpcMessageIdAsProtozero(uint32_t message_id,
     case GinJavaBridgeMsgStart:
       message_class = ChromeLegacyIpc::CLASS_GIN_JAVA_BRIDGE;
       break;
-    case ChromeUtilityPrintingMsgStart:
-      message_class = ChromeLegacyIpc::CLASS_CHROME_UTILITY_PRINTING;
-      break;
     case ExtensionsGuestViewMsgStart:
       message_class = ChromeLegacyIpc::CLASS_EXTENSIONS_GUEST_VIEW;
       break;

tools/ipc_fuzzer/message_tools/message_list.cc

@@ -48,7 +48,6 @@ static bool check_msgtable() {
   // include message files used inside the actual chrome browser in this list.
   exemptions.push_back(TestMsgStart);
   exemptions.push_back(WorkerMsgStart);    // Now only used by tests.
-  exemptions.push_back(ChromeUtilityPrintingMsgStart);  // BUILDFLAGS, sigh.
 
 #if !BUILDFLAG(ENABLE_NACL)
   exemptions.push_back(NaClMsgStart);