[Merge M-57] Add a warning for the deprecation of content-initiated data URL navigations

content/browser/frame_host/navigation_handle_impl.cc

Index: content/browser/frame_host/navigation_handle_impl.cc
diff --git a/content/browser/frame_host/navigation_handle_impl.cc b/content/browser/frame_host/navigation_handle_impl.cc
index 30536bd306c76c4da490f9ea142210612c907d0c..6c884751ddef139afcc3f0c101f13072a1fc9d4c 100644
--- a/content/browser/frame_host/navigation_handle_impl.cc
+++ b/content/browser/frame_host/navigation_handle_impl.cc
@@ -561,6 +561,14 @@ void NavigationHandleImpl::DidCommitNavigation(
   } else {
     state_ = DID_COMMIT;
   }
+
+  if (url_.SchemeIs(url::kDataScheme) && IsInMainFrame() &&
+      IsRendererInitiated()) {
+    GetRenderFrameHost()->AddMessageToConsole(
+        CONSOLE_MESSAGE_LEVEL_WARNING,
+        "Upcoming versions will block content-initiated top frame navigations "
+        "to data: URLs. For more information, see https://goo.gl/BaZAea.");
+  }
 }
 
 void NavigationHandleImpl::Transfer() {