content/gpu: Simplify gpu channel message handling.

content/common/gpu/gpu_channel_manager.h

Index: content/common/gpu/gpu_channel_manager.h
diff --git a/content/common/gpu/gpu_channel_manager.h b/content/common/gpu/gpu_channel_manager.h
index 4de851abf20722e7cb08182f7a6b80901931639d..0fd70b46061a4f8baea196c21d76ed4b0454cd59 100644
--- a/content/common/gpu/gpu_channel_manager.h
+++ b/content/common/gpu/gpu_channel_manager.h
@@ -82,9 +82,6 @@ class CONTENT_EXPORT GpuChannelManager : public IPC::Listener,
   // Sender overrides.
   bool Send(IPC::Message* msg) override;
 
-  uint32_t ProcessedOrderNumber();
-  uint32_t UnprocessedOrderNumber();
-
   void LoseAllContexts();
 
   int GenerateRouteID();
@@ -97,7 +94,7 @@ class CONTENT_EXPORT GpuChannelManager : public IPC::Listener,
 
   GpuMemoryManager* gpu_memory_manager() { return &gpu_memory_manager_; }
 
-  GpuChannel* LookupChannel(int32 client_id);
+  GpuChannel* LookupChannel(int32 client_id) const;
 
   gpu::SyncPointManager* sync_point_manager() {
     return sync_point_manager_;
@@ -109,6 +106,14 @@ class CONTENT_EXPORT GpuChannelManager : public IPC::Listener,
     return gpu_memory_buffer_factory_;
   }
 
+  // Returns the maximum order number for unprocessed IPC messages across all
+  // channels.
+  uint32_t GetUnprocessedOrderNum() const;
+
+  // Returns the maximum order number for processed IPC messages across all
+  // channels.
+  uint32_t GetProcessedOrderNum() const;
+
  protected:
   virtual scoped_ptr<GpuChannel> CreateGpuChannel(
       gfx::GLShareGroup* share_group,