gpu: Have GpuService create and own GpuMemoryBufferFactory.

content/browser/gpu/gpu_main_thread_factory.h

Index: content/browser/gpu/gpu_main_thread_factory.h
diff --git a/content/browser/gpu/gpu_main_thread_factory.h b/content/browser/gpu/gpu_main_thread_factory.h
index d1fba87d78cd5748793b4bc2fe86761e33e1dee9..57ed8bfa4ccad8e015a6348253800ae74f763037 100644
--- a/content/browser/gpu/gpu_main_thread_factory.h
+++ b/content/browser/gpu/gpu_main_thread_factory.h
@@ -11,16 +11,11 @@ namespace base {
 class Thread;
 }
 
-namespace gpu {
-struct GpuPreferences;
-}
-
 namespace content {
 class InProcessChildThreadParams;
 
 typedef base::Thread* (*GpuMainThreadFactoryFunction)(
-    const InProcessChildThreadParams&,
-    const gpu::GpuPreferences&);
+    const InProcessChildThreadParams&);
 
 CONTENT_EXPORT void RegisterGpuMainThreadFactory(
     GpuMainThreadFactoryFunction create);