Make CommandBuffer::Flush asynchronous, and add CommandBuffer::FlushSync with former semantics.

gpu/command_buffer/client/gles2_implementation_unittest.cc

 // Copyright (c) 2009 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.
 
 // Tests for the Command Buffer Helper.
 
 #include "gpu/command_buffer/client/gles2_implementation.h"
 #include "gpu/command_buffer/common/command_buffer.h"
 #include "gpu/GLES2/gles2_command_buffer.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ skipping 19 matching lines @@
   }
 
   virtual Buffer GetRingBuffer() {
     return ring_buffer_buffer_;
   }
 
   virtual State GetState() {
     return state_;
   }
 
-  virtual State Flush(int32 put_offset) {
+  virtual void Flush(int32 put_offset) {
+    FlushSync(put_offset);
+  }
+
+  virtual State FlushSync(int32 put_offset) {
     state_.put_offset = put_offset;
     state_.get_offset = put_offset;
     OnFlush(transfer_buffer_buffer_.ptr);
 
     return state_;
   }
 
   virtual void SetGetOffset(int32 get_offset) {
     state_.get_offset = get_offset;
   }
@@ skipping 902 matching lines @@
   EXPECT_EQ(static_cast<GLenum>(GL_INVALID_ENUM), gl_->GetError());
   const char* kPtr = "something";
   gl_->UnmapTexSubImage2DCHROMIUM(kPtr);
   EXPECT_EQ(static_cast<GLenum>(GL_INVALID_VALUE), gl_->GetError());
 }
 
 }  // namespace gles2
 }  // namespace gpu