PlzNavigate: Support data urls

content/browser/frame_host/navigation_request.h

Index: content/browser/frame_host/navigation_request.h
diff --git a/content/browser/frame_host/navigation_request.h b/content/browser/frame_host/navigation_request.h
index b49d6929d1b9958e313d309f12777f2fb4f83b7e..a88ca281478e1247852eb19d692bca7c7d3bddbc 100644
--- a/content/browser/frame_host/navigation_request.h
+++ b/content/browser/frame_host/navigation_request.h
@@ -70,11 +70,11 @@ class CONTENT_EXPORT NavigationRequest : public NavigationURLLoaderDelegate {
 
   ~NavigationRequest() override;
 
-  // Called on the UI thread by the Navigator to start the navigation on the IO
-  // thread.
+  // Called on the UI thread by the Navigator to start the navigation. Returns
+  // whether a request was made on the IO thread.
   // TODO(clamy): see if ResourceRequestBody could be un-refcounted to avoid
   // threading subtleties.
-  void BeginNavigation();
+  bool BeginNavigation();
 
   const CommonNavigationParams& common_params() const { return common_params_; }