content: Remove gpu memory buffer manager from ChildThreadImpl.

content/child/child_thread_impl.h

Index: content/child/child_thread_impl.h
diff --git a/content/child/child_thread_impl.h b/content/child/child_thread_impl.h
index 34b87e26f6e90b63548b613c0f32f2a32a4a2453..bb878de997a6bc0399bba8bea4eee441189109dc 100644
--- a/content/child/child_thread_impl.h
+++ b/content/child/child_thread_impl.h
@@ -55,7 +55,6 @@ class WebFrame;
 namespace content {
 class ChildMessageFilter;
 class ChildDiscardableSharedMemoryManager;
-class ChildGpuMemoryBufferManager;
 class ChildHistogramMessageFilter;
 class ChildResourceMessageFilter;
 class ChildSharedBitmapManager;
@@ -137,10 +136,6 @@ class CONTENT_EXPORT ChildThreadImpl
     return shared_bitmap_manager_.get();
   }
 
-  ChildGpuMemoryBufferManager* gpu_memory_buffer_manager() const {
-    return gpu_memory_buffer_manager_.get();
-  }
-
   ChildDiscardableSharedMemoryManager* discardable_shared_memory_manager()
       const {
     return discardable_shared_memory_manager_.get();
@@ -320,8 +315,6 @@ class CONTENT_EXPORT ChildThreadImpl
 
   std::unique_ptr<ChildSharedBitmapManager> shared_bitmap_manager_;
 
-  std::unique_ptr<ChildGpuMemoryBufferManager> gpu_memory_buffer_manager_;
-
   std::unique_ptr<ChildDiscardableSharedMemoryManager>
       discardable_shared_memory_manager_;