Remove dead code for IPC channels

We no longer use the code path to add IO-thread associated interfaces
directly to an IPC::Channel, except for some BrowserMessageFilter code
which also turns out to be dead code.

Delete this stuff.

Bug: None
Change-Id: Iad964273134fb953562c3829359117eee11179e5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5530315
Reviewed-by: Nasko Oskov <nasko@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Ken Rockot <rockot@google.com>
Cr-Commit-Position: refs/heads/main@{#1299048}

content/browser/renderer_host/agent_scheduling_group_host.cc

@@ -250,7 +250,6 @@ void AgentSchedulingGroupHost::AddFilter(BrowserMessageFilter* filter) {
     return;
   }
 
-  filter->RegisterAssociatedInterfaces(channel_.get());
   channel_->AddFilter(filter->GetFilter());
 }
 #endif

content/browser/renderer_host/render_process_host_impl.cc

@@ -4301,7 +4301,6 @@ IPC::ChannelProxy* RenderProcessHostImpl::GetChannel() {
 
 #if BUILDFLAG(CONTENT_ENABLE_LEGACY_IPC)
 void RenderProcessHostImpl::AddFilter(BrowserMessageFilter* filter) {
-  filter->RegisterAssociatedInterfaces(channel_.get());
   channel_->AddFilter(filter->GetFilter());
 }
 #endif

content/public/browser/browser_message_filter.cc

@@ -108,8 +108,6 @@ class BrowserMessageFilter::Internal : public IPC::MessageFilter {
   scoped_refptr<BrowserMessageFilter> filter_;
 };
 
-BrowserMessageFilter::BrowserMessageFilter() = default;
-
 BrowserMessageFilter::BrowserMessageFilter(uint32_t message_class_to_filter)
     : message_classes_to_filter_(1, message_class_to_filter) {}
 
@@ -122,14 +120,6 @@ BrowserMessageFilter::BrowserMessageFilter(
   DCHECK(num_message_classes_to_filter);
 }
 
-void BrowserMessageFilter::AddAssociatedInterface(
-    const std::string& name,
-    const IPC::ChannelProxy::GenericAssociatedInterfaceFactory& factory,
-    base::OnceClosure filter_removed_callback) {
-  associated_interfaces_.emplace_back(name, factory);
-  filter_removed_callbacks_.emplace_back(std::move(filter_removed_callback));
-}
-
 base::ProcessHandle BrowserMessageFilter::PeerHandle() {
   return peer_process_.Handle();
 }
@@ -196,11 +186,4 @@ IPC::MessageFilter* BrowserMessageFilter::GetFilter() {
   return internal_;
 }
 
-void BrowserMessageFilter::RegisterAssociatedInterfaces(
-    IPC::ChannelProxy* proxy) {
-  for (const auto& entry : associated_interfaces_)
-    proxy->AddGenericAssociatedInterfaceForIOThread(entry.first, entry.second);
-  associated_interfaces_.clear();
-}
-
 }  // namespace content

content/public/browser/browser_message_filter.h

@@ -27,7 +27,6 @@ class MessageFilter;
 }
 
 namespace content {
-class BrowserAssociatedInterfaceTest;
 struct BrowserMessageFilterTraits;
 
 // Base class for message filters in the browser process.  You can receive and
@@ -42,7 +41,6 @@ class CONTENT_EXPORT BrowserMessageFilter
           BrowserMessageFilter, BrowserMessageFilterTraits>,
       public IPC::Sender {
  public:
-  BrowserMessageFilter();  // For mojo-only BrowserAssociatedInterface.
   explicit BrowserMessageFilter(uint32_t message_class_to_filter);
   BrowserMessageFilter(const uint32_t* message_classes_to_filter,
                        size_t num_message_classes_to_filter);
@@ -88,16 +86,6 @@ class CONTENT_EXPORT BrowserMessageFilter
   // your function will be called on the requested thread.
   virtual bool OnMessageReceived(const IPC::Message& message) = 0;
 
-  // Adds an associated interface factory to this filter. Must be called before
-  // RegisterAssociatedInterfaces().
-  //
-  // |filter_removed_callback| is called on the IO thread when this filter is
-  // removed.
-  void AddAssociatedInterface(
-      const std::string& name,
-      const IPC::ChannelProxy::GenericAssociatedInterfaceFactory& factory,
-      const base::OnceClosure filter_removed_callback);
-
   // Can be called on any thread, after OnChannelConnected is called.
   base::ProcessHandle PeerHandle();
 
@@ -126,17 +114,14 @@ class CONTENT_EXPORT BrowserMessageFilter
 
   class Internal;
   friend class AgentSchedulingGroupHost;
-  friend class BrowserAssociatedInterfaceTest;
   friend class BrowserChildProcessHostImpl;
   friend class BrowserPpapiHost;
   friend class RenderProcessHostImpl;
 
   // These are private because the only classes that need access to them are
   // made friends above. These are only guaranteed to be valid to call on
-  // creation. After that this class could outlive the filter and new interface
-  // registrations could race with incoming requests.
+  // creation. After that this class could outlive the filter.
   IPC::MessageFilter* GetFilter();
-  void RegisterAssociatedInterfaces(IPC::ChannelProxy* proxy);
 
   // This implements IPC::MessageFilter so that we can hide that from child
   // classes. Internal keeps a reference to this class, which is why there's a
@@ -149,10 +134,6 @@ class CONTENT_EXPORT BrowserMessageFilter
 
   std::vector<uint32_t> message_classes_to_filter_;
 
-  std::vector<std::pair<std::string,
-                        IPC::ChannelProxy::GenericAssociatedInterfaceFactory>>
-      associated_interfaces_;
-
   // Callbacks to be called in OnFilterRemoved().
   std::vector<base::OnceClosure> filter_removed_callbacks_;
 };

ipc/ipc_channel.h

@@ -105,28 +105,6 @@ class COMPONENT_EXPORT(IPC) Channel : public Sender {
     // Requests an associated interface from the remote endpoint.
     virtual void GetRemoteAssociatedInterface(
         mojo::GenericPendingAssociatedReceiver receiver) = 0;
-
-    // Template helper to add an interface factory to this channel.
-    template <typename Interface>
-    using AssociatedReceiverFactory = base::RepeatingCallback<void(
-        mojo::PendingAssociatedReceiver<Interface>)>;
-    template <typename Interface>
-    void AddAssociatedInterface(
-        const AssociatedReceiverFactory<Interface>& factory) {
-      AddGenericAssociatedInterface(
-          Interface::Name_,
-          base::BindRepeating(&BindPendingAssociatedReceiver<Interface>,
-                              factory));
-    }
-
-   private:
-    template <typename Interface>
-    static void BindPendingAssociatedReceiver(
-        const AssociatedReceiverFactory<Interface>& factory,
-        mojo::ScopedInterfaceEndpointHandle handle) {
-      factory.Run(
-          mojo::PendingAssociatedReceiver<Interface>(std::move(handle)));
-    }
   };
 
   // The maximum message size in bytes. Attempting to receive a message of this

ipc/ipc_channel_mojo_unittest.cc

@@ -673,129 +673,6 @@ DEFINE_IPC_CHANNEL_MOJO_TEST_CLIENT(IPCChannelMojoTestSendOkClient) {
   Close();
 }
 
-class ListenerWithSimpleAssociatedInterface
-    : public IPC::Listener,
-      public IPC::mojom::SimpleTestDriver {
- public:
-  static const int kNumMessages;
-
-  explicit ListenerWithSimpleAssociatedInterface(base::OnceClosure quit_closure)
-      : quit_closure_(std::move(quit_closure)) {}
-
-  ~ListenerWithSimpleAssociatedInterface() override = default;
-
-  bool OnMessageReceived(const IPC::Message& message) override {
-    base::PickleIterator iter(message);
-    int32_t should_be_expected;
-    EXPECT_TRUE(iter.ReadInt(&should_be_expected));
-    EXPECT_EQ(should_be_expected, next_expected_value_);
-    num_messages_received_++;
-    return true;
-  }
-
-  void OnChannelError() override { CHECK(!quit_closure_); }
-
-  void RegisterInterfaceFactory(IPC::Channel* channel) {
-    channel->GetAssociatedInterfaceSupport()->AddAssociatedInterface(
-        base::BindRepeating(
-            &ListenerWithSimpleAssociatedInterface::BindReceiver,
-            base::Unretained(this)));
-  }
-
- private:
-  // IPC::mojom::SimpleTestDriver:
-  void ExpectValue(int32_t value) override {
-    next_expected_value_ = value;
-  }
-
-  void GetExpectedValue(GetExpectedValueCallback callback) override {
-    NOTREACHED();
-  }
-
-  void RequestValue(RequestValueCallback callback) override { NOTREACHED(); }
-
-  void RequestQuit(RequestQuitCallback callback) override {
-    EXPECT_EQ(kNumMessages, num_messages_received_);
-    std::move(callback).Run();
-    std::move(quit_closure_).Run();
-  }
-
-  void BindReceiver(
-      mojo::PendingAssociatedReceiver<IPC::mojom::SimpleTestDriver> receiver) {
-    DCHECK(!receiver_.is_bound());
-    receiver_.Bind(std::move(receiver));
-  }
-
-  int32_t next_expected_value_ = 0;
-  int num_messages_received_ = 0;
-  base::OnceClosure quit_closure_;
-
-  mojo::AssociatedReceiver<IPC::mojom::SimpleTestDriver> receiver_{this};
-};
-
-const int ListenerWithSimpleAssociatedInterface::kNumMessages = 1000;
-
-class ListenerSendingAssociatedMessages : public IPC::Listener {
- public:
-  explicit ListenerSendingAssociatedMessages(base::OnceClosure quit_closure)
-      : quit_closure_(std::move(quit_closure)) {}
-
-  bool OnMessageReceived(const IPC::Message& message) override { return true; }
-
-  void OnChannelConnected(int32_t peer_pid) override {
-    DCHECK(channel_);
-    channel_->GetAssociatedInterfaceSupport()->GetRemoteAssociatedInterface(
-        driver_.BindNewEndpointAndPassReceiver());
-
-    // Send a bunch of interleaved messages, alternating between the associated
-    // interface and a legacy IPC::Message.
-    for (int i = 0; i < ListenerWithSimpleAssociatedInterface::kNumMessages;
-         ++i) {
-      driver_->ExpectValue(i);
-      SendValue(channel_, i);
-    }
-    driver_->RequestQuit(base::BindOnce(
-        &ListenerSendingAssociatedMessages::OnQuitAck, base::Unretained(this)));
-  }
-
-  void set_channel(IPC::Channel* channel) { channel_ = channel; }
-
- private:
-  void OnQuitAck() { std::move(quit_closure_).Run(); }
-
-  raw_ptr<IPC::Channel> channel_ = nullptr;
-  mojo::AssociatedRemote<IPC::mojom::SimpleTestDriver> driver_;
-  base::OnceClosure quit_closure_;
-};
-
-TEST_F(IPCChannelMojoTest, SimpleAssociatedInterface) {
-  Init("SimpleAssociatedInterfaceClient");
-
-  base::RunLoop run_loop;
-  ListenerWithSimpleAssociatedInterface listener(run_loop.QuitClosure());
-  CreateChannel(&listener);
-  ASSERT_TRUE(ConnectChannel());
-
-  listener.RegisterInterfaceFactory(channel());
-
-  run_loop.Run();
-  channel()->Close();
-
-  EXPECT_TRUE(WaitForClientShutdown());
-  DestroyChannel();
-}
-
-DEFINE_IPC_CHANNEL_MOJO_TEST_CLIENT(SimpleAssociatedInterfaceClient) {
-  base::RunLoop run_loop;
-  ListenerSendingAssociatedMessages listener(run_loop.QuitClosure());
-  Connect(&listener);
-  listener.set_channel(channel());
-
-  run_loop.Run();
-
-  Close();
-}
-
 class ChannelProxyRunner {
  public:
   ChannelProxyRunner(mojo::ScopedMessagePipeHandle handle,