gpu: Add GpuFence framework.

gpu/command_buffer/service/gles2_cmd_decoder.h

Index: gpu/command_buffer/service/gles2_cmd_decoder.h
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.h b/gpu/command_buffer/service/gles2_cmd_decoder.h
index ae22695178503e14cb78f016cf9b56a69d4d95b0..cf6683ee3e5d46c8b5d4d35649d317f4b082e496 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.h
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.h
@@ -42,6 +42,7 @@ namespace gles2 {
 class ContextGroup;
 class ErrorState;
 class FeatureInfo;
+class FenceManager;
 class GLES2Util;
 class ImageManager;
 class Logger;
@@ -219,6 +220,9 @@ class GPU_EXPORT GLES2Decoder : public base::SupportsWeakPtr<GLES2Decoder>,
   // Gets the ImageManager for this context.
   virtual ImageManager* GetImageManager() = 0;
 
+  // Gets the FenceManager for this context.
+  virtual FenceManager* GetFenceManager() = 0;
+
   // Returns false if there are no pending queries.
   virtual bool HasPendingQueries() const = 0;