Remove the is_loading_ field from WebContentsImpl

content/browser/frame_host/frame_tree_node.h

Index: content/browser/frame_host/frame_tree_node.h
diff --git a/content/browser/frame_host/frame_tree_node.h b/content/browser/frame_host/frame_tree_node.h
index eac49777a663150917ab2289073e2dd3f8dc4d6b..4ea612350f35ebecf80f0d3ec8736c5212fa620a 100644
--- a/content/browser/frame_host/frame_tree_node.h
+++ b/content/browser/frame_host/frame_tree_node.h
@@ -235,7 +235,11 @@ class CONTENT_EXPORT FrameTreeNode {
   // A RenderFrameHost in this node started loading.
   // |to_different_document| will be true unless the load is a fragment
   // navigation, or triggered by history.pushState/replaceState.
-  void DidStartLoading(bool to_different_document);
+  // |was_previously_loading| is false if the FrameTree was not loading before.
+  // The caller is required to provide this boolean as the delegate should only
+  // be called if the FrameTree went from non-loading to loading state.
+  // However, when it is called, the FrameTree should be in a loading state.
+  void DidStartLoading(bool to_different_document, bool was_previously_loading);
 
   // A RenderFrameHost in this node stopped loading.
   void DidStopLoading();
@@ -257,6 +261,10 @@ class CONTENT_EXPORT FrameTreeNode {
   // time and notifies observers.
   void DidFocus();
 
+  // Called when the user closed the modal dialogue for BeforeUnload and
+  // cancelled the navigation. This should stop the loads.
+  void BeforeUnloadCanceled();
+
  private:
   class OpenerDestroyedObserver;