content/gpu: Set up a mojom connection between browser and gpu.

content/browser/browser_child_process_host_impl.h

Index: content/browser/browser_child_process_host_impl.h
diff --git a/content/browser/browser_child_process_host_impl.h b/content/browser/browser_child_process_host_impl.h
index ff9c3291f89566ea9a6d5797976884c7e4471360..0b2906f218221c2632d40767431591ef134c11f6 100644
--- a/content/browser/browser_child_process_host_impl.h
+++ b/content/browser/browser_child_process_host_impl.h
@@ -84,6 +84,7 @@ class CONTENT_EXPORT BrowserChildProcessHostImpl
 
   // ChildProcessHostDelegate implementation:
   bool CanShutdown() override;
+  void OnChannelInitialized(IPC::Channel* channel) override;
   void OnChildDisconnected() override;
   const base::Process& GetProcess() const override;
   service_manager::InterfaceProvider* GetRemoteInterfaces() override;
@@ -113,6 +114,8 @@ class CONTENT_EXPORT BrowserChildProcessHostImpl
     return child_connection_.get();
   }
 
+  IPC::Channel* child_channel() const { return channel_; }
+
   typedef std::list<BrowserChildProcessHostImpl*> BrowserChildProcessList;
  private:
   friend class BrowserChildProcessHostIterator;
@@ -168,6 +171,7 @@ class CONTENT_EXPORT BrowserChildProcessHostImpl
   // The memory allocator, if any, in which the process will write its metrics.
   std::unique_ptr<base::SharedPersistentMemoryAllocator> metrics_allocator_;
 
+  IPC::Channel* channel_ = nullptr;
   bool is_channel_connected_;
   bool notify_child_disconnected_;