Make OffscreenCanvas resizable

third_party/WebKit/Source/platform/graphics/OffscreenCanvasFrameDispatcherImpl.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/OffscreenCanvasFrameDispatcherImpl.h"
 
 #include "cc/output/compositor_frame.h"
 #include "cc/quads/texture_draw_quad.h"
 #include "gpu/command_buffer/client/gles2_interface.h"
 #include "platform/CrossThreadFunctional.h"
@@ skipping 18 matching lines @@
 
 OffscreenCanvasFrameDispatcherImpl::OffscreenCanvasFrameDispatcherImpl(
     uint32_t clientId,
     uint32_t sinkId,
     int canvasId,
     int width,
     int height)
     : m_frameSinkId(cc::FrameSinkId(clientId, sinkId)),
       m_width(width),
       m_height(height),
+      m_changeSizeForNextCommit(false),
       m_nextResourceId(1u),
       m_binding(this),
       m_placeholderCanvasId(canvasId) {
   m_currentLocalFrameId = m_surfaceIdAllocator.GenerateId();
   DCHECK(!m_sink.is_bound());
   mojom::blink::OffscreenCanvasCompositorFrameSinkProviderPtr provider;
   Platform::current()->interfaceProvider()->getInterface(
       mojo::MakeRequest(&provider));
   provider->CreateCompositorFrameSink(m_frameSinkId,
                                       m_binding.CreateInterfacePtrAndBind(),
@@ skipping 301 matching lines @@
                                      "SoftwareCanvasSoftwareCompositingWorker",
                                      0, 10000000, 50));
         commitSoftwareCanvasSoftwareCompositingWorkerTimer.count(elapsedTime *
                                                                  1000000.0);
       }
       break;
     case OffscreenCanvasCommitTypeCount:
       NOTREACHED();
   }
 
+  if (m_changeSizeForNextCommit) {
+    m_currentLocalFrameId = m_surfaceIdAllocator.GenerateId();
+    m_changeSizeForNextCommit = false;
+  }
   m_sink->SubmitCompositorFrame(m_currentLocalFrameId, std::move(frame));
 }
 
 void OffscreenCanvasFrameDispatcherImpl::DidReceiveCompositorFrameAck() {
   // TODO(fsamuel): Implement this.
 }
 
 void OffscreenCanvasFrameDispatcherImpl::OnBeginFrame(
     const cc::BeginFrameArgs& beginFrameArgs) {}
 
@@ skipping 29 matching lines @@
 }
 
 bool OffscreenCanvasFrameDispatcherImpl::verifyImageSize(
     const IntSize imageSize) {
   if (imageSize.width() == m_width && imageSize.height() == m_height)
     return true;
   return false;
 }
 
 void OffscreenCanvasFrameDispatcherImpl::reshape(int width, int height) {
-  m_width = width;
-  m_height = height;
+  if (m_width != width || m_height != height) {
+    m_width = width;
+    m_height = height;
+    m_changeSizeForNextCommit = true;
+  }
 }
 
 }  // namespace blink