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

gpu/command_buffer/client/gles2_implementation_unittest.cc

Index: gpu/command_buffer/client/gles2_implementation_unittest.cc
diff --git a/gpu/command_buffer/client/gles2_implementation_unittest.cc b/gpu/command_buffer/client/gles2_implementation_unittest.cc
index d431851e503d73b1234f7f03f80cc8e78c70d1cd..dabcba354846c46209c901236f6a71642a8dd7f3 100644
--- a/gpu/command_buffer/client/gles2_implementation_unittest.cc
+++ b/gpu/command_buffer/client/gles2_implementation_unittest.cc
@@ -37,7 +37,11 @@ class GLES2MockCommandBufferHelper : public CommandBuffer {
     return state_;
   }
 
-  virtual State Flush(int32 put_offset) {
+  virtual void Flush(int32 put_offset) {
+    state_.put_offset = put_offset;
+  }
+
+  virtual State FlushSync(int32 put_offset) {
     state_.put_offset = put_offset;
     state_.get_offset = put_offset;
     OnFlush(transfer_buffer_buffer_.ptr);
@@ -191,7 +195,7 @@ class GLES2ImplementationTest : public testing::Test {
         false));
 
     EXPECT_CALL(*command_buffer_, OnFlush(_)).Times(1).RetiresOnSaturation();
-    helper_->CommandBufferHelper::Flush();
+    helper_->CommandBufferHelper::FlushSync();
     Buffer ring_buffer = command_buffer_->GetRingBuffer();
     commands_ = static_cast<CommandBufferEntry*>(ring_buffer.ptr) +
                 command_buffer_->GetState().put_offset;