Added CommandBuffer::GetLastError.

gpu/command_buffer/common/command_buffer.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef GPU_COMMAND_BUFFER_COMMON_COMMAND_BUFFER_H_
 #define GPU_COMMAND_BUFFER_COMMON_COMMAND_BUFFER_H_
 
 #include "../common/buffer.h"
 #include "../common/constants.h"
 
@@ skipping 116 matching lines @@
   virtual void SetToken(int32 token) = 0;
 
   // Allows the reader to set the current parse error.
   virtual void SetParseError(error::Error) = 0;
 
   // Allows the reader to set the current context lost reason.
   // NOTE: if calling this in conjunction with SetParseError,
   // call this first.
   virtual void SetContextLostReason(error::ContextLostReason) = 0;
 
+  // TODO(apatrick): this is a temporary optimization while skia is calling
+  // RendererGLContext::MakeCurrent prior to every GL call. It saves returning 6
+  // ints redundantly when only the error is needed for the CommandBufferProxy
+  // implementation.
+  virtual error::Error GetLastError();
+
  private:
   DISALLOW_COPY_AND_ASSIGN(CommandBuffer);
 };
 
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_COMMON_COMMAND_BUFFER_H_