[unseasoned-pdf] Create PdfViewWebPlugin

Creates the unseasoned plugin (PdfViewWebPlugin) instead of the Pepper
plugin (OutOfProcessInstance) when the `enable_pdf_unseasoned` buildflag
is set.

Up until this change, developers working on unseasoning the PDF viewer
needed to patch in an equivalent change temporarily. This is tedious and
error-prone, so we want to commit this code into the repository.

This change creates the plugin in the PDF viewer extension process,
which is not secure. This will be fixed by a new process model for the
PDF viewer (crbug.com/1123621), but we don't want to block on that work.

To minimize the security risk, the new plugin must be enabled at
compile-time using a buildflag; this code is meant for developers-only.

The plugin is created in ChromeContentRendererClient::CreatePlugin()
directly, rather than going through the plugin registry, which only can
handle Pepper plugins. The new plugin acts as a drop-in replacement for
the Pepper plugin.

Bug: 1123629
Change-Id: Ib4644f037a9d6df0410f82f7d8338d6907c79d80
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2310870
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Tommy Li <tommycli@chromium.org>
Reviewed-by: Filip Gorski <fgorski@chromium.org>
Commit-Queue: K. Moon <kmoon@chromium.org>
Cr-Commit-Position: refs/heads/master@{#860020}

chrome/renderer/BUILD.gn

@@ -206,6 +206,8 @@ static_library("renderer") {
     "//media/capture",
     "//mojo/public/cpp/bindings",
     "//net",
+    "//pdf:buildflags",
+    "//pdf:pdf_view_web_plugin",
     "//ppapi/buildflags",
     "//printing/buildflags",
     "//services/metrics/public/cpp:metrics_cpp",

chrome/renderer/DEPS

@@ -75,6 +75,7 @@ include_rules = [
   "+google_apis",
   "+media/base",
   "+media/mojo",
+  "+pdf/pdf_view_web_plugin.h",
   "+ppapi/shared_impl",
   "+services/network/public/cpp",
   "+services/network/public/mojom",

chrome/renderer/chrome_content_renderer_client.cc

@@ -127,6 +127,7 @@
 #include "mojo/public/cpp/bindings/generic_pending_receiver.h"
 #include "mojo/public/cpp/bindings/remote.h"
 #include "net/base/net_errors.h"
+#include "pdf/buildflags.h"
 #include "ppapi/buildflags/buildflags.h"
 #include "printing/buildflags/buildflags.h"
 #include "services/network/public/cpp/is_potentially_trustworthy.h"
@@ -194,6 +195,10 @@
 #include "third_party/blink/public/web/web_view.h"
 #endif
 
+#if BUILDFLAG(ENABLE_PDF_UNSEASONED)
+#include "pdf/pdf_view_web_plugin.h"
+#endif
+
 #if BUILDFLAG(ENABLE_PLUGINS)
 #include "chrome/common/plugin_utils.h"
 #include "chrome/renderer/plugins/chrome_plugin_placeholder.h"
@@ -986,6 +991,16 @@ WebPlugin* ChromeContentRendererClient::CreatePlugin(
           break;
         }
 
+#if BUILDFLAG(ENABLE_PDF_UNSEASONED)
+        if (info.name ==
+            ASCIIToUTF16(ChromeContentClient::kPDFInternalPluginName)) {
+          // Create unseasoned PDF plugin directly, for development purposes.
+          // TODO(crbug.com/1123621): Implement a more permanent solution once
+          // the new PDF viewer process model is approved and in place.
+          return new chrome_pdf::PdfViewWebPlugin(params);
+        }
+#endif  // BUILDFLAG(ENABLE_PDF_UNSEASONED)
+
         return render_frame->CreatePlugin(info, params);
       }
       case chrome::mojom::PluginStatus::kDisabled: {

pdf/BUILD.gn

@@ -13,7 +13,10 @@ import("//v8/gni/v8.gni")
 # Generate a buildflag header for compile-time checking of PDF support.
 buildflag_header("buildflags") {
   header = "buildflags.h"
-  flags = [ "ENABLE_PDF=$enable_pdf" ]
+  flags = [
+    "ENABLE_PDF=$enable_pdf",
+    "ENABLE_PDF_UNSEASONED=$enable_pdf_unseasoned",
+  ]
 }
 
 if (enable_pdf) {
@@ -49,7 +52,6 @@ if (enable_pdf) {
       ":internal",
       ":out_of_process_instance",
       ":pdf",
-      ":pdf_view_web_plugin",
       "//base",
       "//ppapi/cpp:objects",
       "//ppapi/cpp/private:internal_module",
@@ -276,12 +278,14 @@ if (enable_pdf) {
   }
 
   # Eventual replacement for out_of_process_instance.
-  source_set("pdf_view_web_plugin") {
-    visibility = [ ":*" ]
+  static_library("pdf_view_web_plugin") {
+    visibility = [
+      ":*",
+      "//chrome/renderer",
+    ]
 
     sources = [
       "pdf_view_web_plugin.cc",
-      "pdf_view_web_plugin.h",
       "post_message_receiver.cc",
       "post_message_receiver.h",
       "post_message_sender.cc",
@@ -290,6 +294,8 @@ if (enable_pdf) {
 
     configs += [ ":pdf_common_config" ]
 
+    public = [ "pdf_view_web_plugin.h" ]
+
     deps = [
       ":accessibility_structs",
       ":internal",
@@ -376,6 +382,7 @@ if (enable_pdf) {
       ":out_of_process_instance",
       ":pdf",
       ":pdf_test_utils",
+      ":pdf_view_web_plugin",
       ":ppapi_migration",
       "//base",
       "//base:i18n",
@@ -419,4 +426,6 @@ if (enable_pdf) {
   }
   group("pdf_ppapi") {
   }
+  group("pdf_view_web_plugin") {
+  }
 }

pdf/features.gni

@@ -10,4 +10,12 @@ import("//build/config/chromecast_build.gni")
 
 declare_args() {
   enable_pdf = !is_android && !is_ios && !is_chromecast
+
+  # Enable additional code for the Pepper-free PDF viewer.
+  #
+  # This argument enables additional code paths that are only useful during the
+  # PDF viewer's migration from Pepper. This argument is intended to guard code
+  # meant only for developers, and will be phased out before launch in favor of
+  # a run-time feature flag.
+  enable_pdf_unseasoned = false
 }