implement getBufferSubDataAsync prototype

third_party/WebKit/Source/platform/graphics/gpu/DrawingBufferSoftwareRenderingTest.cpp

 // Copyright 2016 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.
 
 #include "platform/graphics/gpu/DrawingBuffer.h"
 
 #include "cc/resources/single_release_callback.h"
 #include "cc/resources/texture_mailbox.h"
 #include "gpu/command_buffer/client/gles2_interface_stub.h"
 #include "platform/graphics/gpu/DrawingBufferTestHelpers.h"
@@ skipping 19 matching lines @@
   gpu::gles2::GLES2Interface* contextGL() override { return m_gl.get(); }
   bool isSoftwareRendering() const override { return true; }
 
   // Not used by WebGL code.
   GrContext* grContext() override { return nullptr; }
   bool bindToCurrentThread() override { return false; }
   gpu::Capabilities getCapabilities() override { return gpu::Capabilities(); }
   void setLostContextCallback(const base::Closure&) {}
   void setErrorMessageCallback(
       const base::Callback<void(const char*, int32_t id)>&) {}
+  void signalQuery(uint32_t, const base::Closure&) override {}
 
  private:
   std::unique_ptr<gpu::gles2::GLES2Interface> m_gl;
 };
 
 class DrawingBufferSoftwareRenderingTest : public Test {
  protected:
   void SetUp() override {
     IntSize initialSize(InitialWidth, InitialHeight);
     std::unique_ptr<GLES2InterfaceForTests> gl =
@@ skipping 44 matching lines @@
       &releaseCallback3);  // cause recycling queue to be purged due to resize
   EXPECT_EQ(0, m_drawingBuffer->recycledBitmapCount());
   releaseCallback3->Run(gpu::SyncToken(), false /* lostResource */);
   EXPECT_EQ(1, m_drawingBuffer->recycledBitmapCount());
 
   m_drawingBuffer->beginDestruction();
 }
 
 }  // unnamed namespace
 }  // blink