Implement OffscreenCanvas.commit() on Unaccelerated 2D on worker

content/renderer/renderer_blink_platform_impl.cc

Index: content/renderer/renderer_blink_platform_impl.cc
diff --git a/content/renderer/renderer_blink_platform_impl.cc b/content/renderer/renderer_blink_platform_impl.cc
index 212a9ec7dc2af291e0c7bac2dc2ad23a51cb1a8a..94b0075f80691d2fcb30c1647a7ca28b122b81b8 100644
--- a/content/renderer/renderer_blink_platform_impl.cc
+++ b/content/renderer/renderer_blink_platform_impl.cc
@@ -278,6 +278,8 @@ RendererBlinkPlatformImpl::RendererBlinkPlatformImpl(
     sync_message_filter_ = ChildThreadImpl::current()->sync_message_filter();
     thread_safe_sender_ = ChildThreadImpl::current()->thread_safe_sender();
     quota_message_filter_ = ChildThreadImpl::current()->quota_message_filter();
+    shared_bitmap_manager_ =
+        ChildThreadImpl::current()->shared_bitmap_manager();
     blob_registry_.reset(new WebBlobRegistryImpl(
         RenderThreadImpl::current()->GetIOTaskRunner().get(),
         base::ThreadTaskRunnerHandle::Get(), thread_safe_sender_.get()));
@@ -293,6 +295,7 @@ RendererBlinkPlatformImpl::RendererBlinkPlatformImpl(
 RendererBlinkPlatformImpl::~RendererBlinkPlatformImpl() {
   WebFileSystemImpl::DeleteThreadSpecificInstance();
   renderer_scheduler_->SetTopLevelBlameContext(nullptr);
+  shared_bitmap_manager_ = nullptr;
 }
 
 void RendererBlinkPlatformImpl::Shutdown() {
@@ -1143,8 +1146,7 @@ RendererBlinkPlatformImpl::createSharedOffscreenGraphicsContext3DProvider() {
 
 std::unique_ptr<cc::SharedBitmap>
 RendererBlinkPlatformImpl::allocateSharedBitmap(const blink::WebSize& size) {
-  return ChildThreadImpl::current()
-      ->shared_bitmap_manager()
+  return shared_bitmap_manager_
       ->AllocateSharedBitmap(gfx::Size(size.width, size.height));
 }