GPU client side changes for GpuMemoryBuffers

gpu/command_buffer/client/gpu_memory_buffer.h

Index: gpu/command_buffer/client/gpu_memory_buffer.h
diff --git a/gpu/command_buffer/client/gpu_memory_buffer.h b/gpu/command_buffer/client/gpu_memory_buffer.h
index aaeb5a9f2c843c589b722c42e5f70ae0c478cdaa..aa7cb6bb998e9404381fbe9b16494d5f87d87410 100644
--- a/gpu/command_buffer/client/gpu_memory_buffer.h
+++ b/gpu/command_buffer/client/gpu_memory_buffer.h
@@ -23,7 +23,7 @@ namespace gpu {
 // behavior and is not allowed.
 class GLES2_IMPL_EXPORT GpuMemoryBuffer {
  public:
-  typedef base::Callback<scoped_ptr<GpuMemoryBuffer>(int, int)> Creator;
+  typedef base::Callback<scoped_ptr<GpuMemoryBuffer>(int, int, int)> Creator;
   enum AccessMode {
     READ_ONLY,
     WRITE_ONLY,
@@ -43,6 +43,9 @@ class GLES2_IMPL_EXPORT GpuMemoryBuffer {
   // completed.
   virtual void Unmap() = 0;
 
+  // Returns true iff the buffer is mapped.
+  virtual bool IsMapped() = 0;
+
   // Returns the native pointer for the buffer.
   virtual void* GetNativeBuffer() = 0;