Inside of content, prefer SiteInstanceImpl to SiteInstance.

content/browser/web_contents/web_contents_impl.cc

Index: content/browser/web_contents/web_contents_impl.cc
diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index 4a747f40931d86f6befceb1a96e34560b12795dc..b56dd17e7ed0fa84904871239866705c70994ab6 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -1271,6 +1271,9 @@ void WebContentsImpl::DispatchBeforeUnload(bool for_cross_site_transition) {
 void WebContentsImpl::AttachToOuterWebContentsFrame(
     WebContents* outer_web_contents,
     RenderFrameHost* outer_contents_frame) {
+  DCHECK(outer_contents_frame);
+  RenderFrameHostImpl* outer_contents_frame_impl =
+      static_cast<RenderFrameHostImpl*>(outer_contents_frame);
   CHECK(BrowserPluginGuestMode::UseCrossProcessFramesForGuests());
   RenderFrameHostManager* render_manager = GetRenderManager();
 
@@ -1289,16 +1292,13 @@ void WebContentsImpl::AttachToOuterWebContentsFrame(
   node_.reset(new WebContentsTreeNode());
   node_->ConnectToOuterWebContents(
       static_cast<WebContentsImpl*>(outer_web_contents),
-      static_cast<RenderFrameHostImpl*>(outer_contents_frame));
-
-  DCHECK(outer_contents_frame);
+      outer_contents_frame_impl);
 
   // Create a proxy in top-level RenderFrameHostManager, pointing to the
   // SiteInstance of the outer WebContents. The proxy will be used to send
   // postMessage to the inner WebContents.
   render_manager->CreateOuterDelegateProxy(
-      outer_contents_frame->GetSiteInstance(),
-      static_cast<RenderFrameHostImpl*>(outer_contents_frame));
+      outer_contents_frame_impl->GetSiteInstance(), outer_contents_frame_impl);
 
   render_manager->SetRWHViewForInnerContents(
       render_manager->GetRenderWidgetHostView());
@@ -1377,9 +1377,10 @@ void WebContentsImpl::Init(const WebContents::CreateParams& params) {
           params.main_frame_routing_id != MSG_ROUTING_NONE &&
           params.main_frame_widget_routing_id != MSG_ROUTING_NONE));
 
-  scoped_refptr<SiteInstance> site_instance = params.site_instance;
+  scoped_refptr<SiteInstanceImpl> site_instance =
+      static_cast<SiteInstanceImpl*>(params.site_instance.get());
   if (!site_instance)
-    site_instance = SiteInstance::Create(params.browser_context);
+    site_instance = SiteInstanceImpl::Create(params.browser_context);
 
   // A main RenderFrameHost always has a RenderWidgetHost, since it is always a
   // local root by definition.