Inside of content, prefer SiteInstanceImpl to SiteInstance.

content/browser/frame_host/render_frame_host_impl.cc

Index: content/browser/frame_host/render_frame_host_impl.cc
diff --git a/content/browser/frame_host/render_frame_host_impl.cc b/content/browser/frame_host/render_frame_host_impl.cc
index 1b0946ed27a3be5f7a206ee54f60ed6e959bd417..da1c0bde147b000c2049b6e047f6866182f469ba 100644
--- a/content/browser/frame_host/render_frame_host_impl.cc
+++ b/content/browser/frame_host/render_frame_host_impl.cc
@@ -178,7 +178,7 @@ RenderFrameHostImpl* RenderFrameHostImpl::FromAXTreeID(
   return RenderFrameHostImpl::FromID(frame_id.first, frame_id.second);
 }
 
-RenderFrameHostImpl::RenderFrameHostImpl(SiteInstance* site_instance,
+RenderFrameHostImpl::RenderFrameHostImpl(SiteInstanceImpl* site_instance,
                                          RenderViewHostImpl* render_view_host,
                                          RenderFrameHostDelegate* delegate,
                                          RenderWidgetHostDelegate* rwh_delegate,
@@ -189,7 +189,7 @@ RenderFrameHostImpl::RenderFrameHostImpl(SiteInstance* site_instance,
                                          bool hidden)
     : render_view_host_(render_view_host),
       delegate_(delegate),
-      site_instance_(static_cast<SiteInstanceImpl*>(site_instance)),
+      site_instance_(site_instance),
       process_(site_instance->GetProcess()),
       cross_process_frame_connector_(NULL),
       render_frame_proxy_host_(NULL),
@@ -651,7 +651,7 @@ gfx::Rect RenderFrameHostImpl::AccessibilityTransformToRootCoordSpace(
                    new_bounds.width(), new_bounds.height());
 }
 
-SiteInstance* RenderFrameHostImpl::AccessibilityGetSiteInstance() {
+SiteInstanceImpl* RenderFrameHostImpl::AccessibilityGetSiteInstance() {
   return GetSiteInstance();
 }
 
@@ -2051,7 +2051,7 @@ void RenderFrameHostImpl::NavigateToInterstitialURL(const GURL& data_url) {
 }
 
 void RenderFrameHostImpl::OpenURL(const FrameHostMsg_OpenURL_Params& params,
-                                  SiteInstance* source_site_instance) {
+                                  SiteInstanceImpl* source_site_instance) {
   GURL validated_url(params.url);
   GetProcess()->FilterURL(false, &validated_url);