pushState should not be treated as a navigation (step 1 of 3)

Add a new version of RenderViewImpl::didStartLoading() that takes a boolean
indicating whether the navigation is to the same document or a different
document. blink will call this new version in a later patch.

BUG=50298

Review URL: https://codereview.chromium.org/102563003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@243122 0039d316-1c4b-4281-b951-d872f2087c98

content/renderer/render_view_impl.cc

@@ -2412,6 +2412,10 @@ void RenderViewImpl::initializeHelperPluginWebFrame(
   plugin->initializeFrame(main_render_frame_.get());
 }
 
+void RenderViewImpl::didStartLoading(bool to_different_document) {
+  didStartLoading();
+}
+
 void RenderViewImpl::didStartLoading() {
   if (is_loading_) {
     DVLOG(1) << "didStartLoading called while loading";

content/renderer/render_view_impl.h

@@ -420,6 +420,8 @@ class CONTENT_EXPORT RenderViewImpl
       const blink::WebString& path,
       blink::WebFileChooserCompletion* chooser_completion);
   virtual void initializeHelperPluginWebFrame(blink::WebHelperPlugin*);
+  virtual void didStartLoading(bool to_different_document);
+  // DEPRECATED
   virtual void didStartLoading();
   virtual void didStopLoading();
   virtual void didChangeLoadProgress(blink::WebFrame* frame,