Refactor Blink's ServiceConnector and add ability to mock in layout tests

content/renderer/renderer_blink_platform_impl.h

Index: content/renderer/renderer_blink_platform_impl.h
diff --git a/content/renderer/renderer_blink_platform_impl.h b/content/renderer/renderer_blink_platform_impl.h
index 2bbee4c3e154089980e44b6c3234a4c9adf55ad4..53eea353926637670f24d05de98adcaacc6a4d6a 100644
--- a/content/renderer/renderer_blink_platform_impl.h
+++ b/content/renderer/renderer_blink_platform_impl.h
@@ -52,6 +52,7 @@ class InterfaceProvider;
 }
 
 namespace content {
+class BlinkConnectorImpl;
 class BlinkInterfaceProviderImpl;
 class LocalStorageCachedAreas;
 class PlatformEventObserverBase;
@@ -185,6 +186,7 @@ class CONTENT_EXPORT RendererBlinkPlatformImpl : public BlinkPlatformImpl {
       const blink::WebSize& size) override;
   blink::WebCompositorSupport* compositorSupport() override;
   blink::WebString convertIDNToUnicode(const blink::WebString& host) override;
+  blink::Connector* connector() override;

[dcheng, 2017/03/21 18:56:18]

Optional nit: one alternative to consider is using a covariant return type here.
It means we need the full definition of BlinkConnectorImpl in this header, but
then we can have connector() directly return BlinkConnectorImpl* here,
eliminating the need for the downcast in RenderFrameImpl.

[blundell, 2017/03/23 10:40:33]

Done.

   blink::InterfaceProvider* interfaceProvider() override;
   void startListening(blink::WebPlatformEventType,
                       blink::WebPlatformEventListener*) override;
@@ -297,6 +299,8 @@ class CONTENT_EXPORT RendererBlinkPlatformImpl : public BlinkPlatformImpl {
 
   std::unique_ptr<LocalStorageCachedAreas> local_storage_cached_areas_;
 
+  std::unique_ptr<BlinkConnectorImpl> blink_connector_;
+
   std::unique_ptr<BlinkInterfaceProviderImpl> blink_interface_provider_;
 
   mojom::URLLoaderFactoryAssociatedPtr url_loader_factory_;