Move content's shell connections to the IO thread

content/gpu/gpu_child_thread.cc

Index: content/gpu/gpu_child_thread.cc
diff --git a/content/gpu/gpu_child_thread.cc b/content/gpu/gpu_child_thread.cc
index a81892212b99691f016740f34d36d04d53904e5c..271cde79bcc5921cc5e732a8d4775495946a83ac 100644
--- a/content/gpu/gpu_child_thread.cc
+++ b/content/gpu/gpu_child_thread.cc
@@ -36,6 +36,7 @@
 #include "media/gpu/ipc/service/gpu_video_decode_accelerator.h"
 #include "media/gpu/ipc/service/gpu_video_encode_accelerator.h"
 #include "media/gpu/ipc/service/media_service.h"
+#include "services/shell/public/cpp/interface_registry.h"
 #include "ui/gl/gl_implementation.h"
 #include "ui/gl/gl_switches.h"
 #include "ui/gl/gpu_switching_manager.h"
@@ -221,6 +222,20 @@ void GpuChildThread::Init(const base::Time& process_start_time) {
   // Only set once per process instance.
   process_control_.reset(new GpuProcessControlImpl());
 
+  // Use of base::Unretained(this) is safe here because |service_registry()|

[Ben Goodger (Google), 2016/07/03 03:29:27]

This seems worse than before - given that you don't have the ability to inspect
the incoming connection before you expose interfaces?

[Ken Rockot(use gerrit already), 2016/07/04 18:22:58]

Right, so it's not really worse in practice since these interfaces weren't
filtered based on any property of the incoming connection. This isn't what
interface registration should look like, but currently all interface
registration is expected to happen on the main thread, and this CL has to move
the relevant shell::Connections to the IO thread. AcceptConnection can't do its
work asynchronously or it would race with incoming connections. Also this part
of the CL wasn't complete when I sent it out.

Now I've changed ProcessControl exposure to be done via a ConnectionFilter which
lives on the IO thread.

It's necessary to have ConnectionFilters live on the IO thread, but it's also
super awkward when they want to register interfaces that should be bound on the
main thread. I would like to devise some reusable helpers for this, but since
there are only a handful of cases that exist today, I've opted to roll one-off
solutions for this CL (see ChromeInterfaceRegistry and
RenderWidgetWindowTreeClientWhateverRidiculousName for examples.)

+  // will be destroyed before GpuChildThread is destructed.
+  GetInterfaceRegistry()->AddInterface(base::Bind(
+      &GpuChildThread::BindProcessControlRequest, base::Unretained(this)));
+
+  if (GetContentClient()->gpu()) {  // NULL in tests.
+    GetContentClient()->gpu()->ExposeInterfacesToBrowser(
+        GetInterfaceRegistry());
+  }
+
+  // We don't want to process any incoming interface requests until
+  // OnInitialize() is invoked.
+  GetInterfaceRegistry()->PauseBinding();
+
   if (GetContentClient()->gpu())  // NULL in tests.
     GetContentClient()->gpu()->Initialize(this);
 }
@@ -290,37 +305,6 @@ bool GpuChildThread::OnMessageReceived(const IPC::Message& msg) {
   return false;
 }
 
-bool GpuChildThread::AcceptConnection(shell::Connection* connection) {
-  // Use of base::Unretained(this) is safe here because |service_registry()|
-  // will be destroyed before GpuChildThread is destructed.
-  connection->GetInterfaceRegistry()->AddInterface(base::Bind(
-      &GpuChildThread::BindProcessControlRequest, base::Unretained(this)));
-
-  if (GetContentClient()->gpu()) {  // NULL in tests.
-    GetContentClient()->gpu()->ExposeInterfacesToBrowser(
-        connection->GetInterfaceRegistry());
-  }
-
-  // We don't want to process any incoming interface requests until
-  // OnInitialize().
-  if (!gpu_channel_manager_) {
-    connection->GetInterfaceRegistry()->PauseBinding();
-    resume_interface_bindings_callback_ = base::Bind(
-        &shell::InterfaceRegistry::ResumeBinding,
-        connection->GetInterfaceRegistry()->GetWeakPtr());
-  }
-
-  return true;
-}
-
-shell::InterfaceRegistry* GpuChildThread::GetInterfaceRegistryForConnection() {
-  return nullptr;
-}
-
-shell::InterfaceProvider* GpuChildThread::GetInterfaceProviderForConnection() {
-  return nullptr;
-}
-
 void GpuChildThread::SetActiveURL(const GURL& url) {
   GetContentClient()->SetActiveURL(url);
 }
@@ -364,8 +348,7 @@ void GpuChildThread::StoreShaderToDisk(int32_t client_id,
 }
 
 void GpuChildThread::OnInitialize(const gpu::GpuPreferences& gpu_preferences) {
-  if (!resume_interface_bindings_callback_.is_null())
-    base::ResetAndReturn(&resume_interface_bindings_callback_).Run();
+  GetInterfaceRegistry()->ResumeBinding();
 
   gpu_preferences_ = gpu_preferences;