Add mouse input forwarding to gpu service

gpu/command_buffer/service/gles2_cmd_decoder.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.cc b/gpu/command_buffer/service/gles2_cmd_decoder.cc
index 363ecf8af508dda5f431f046ee2e191e56dfb96e..78115bd8ba7afbab54c128295b848a4816918f85 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -630,7 +630,13 @@ class GLES2DecoderImpl : public GLES2Decoder,
     return vertex_array_manager_.get();
   }
   ImageManager* GetImageManager() override { return image_manager_.get(); }
+
+  ValuebufferManager* GetValuebufferManager() override {
+    return valuebuffer_manager();
+  }
+
   bool ProcessPendingQueries(bool did_finish) override;
+
   bool HasMoreIdleWork() override;
   void PerformIdleWork() override;