PlzNavigate: Allow frames to fallback to alternative content.

third_party/WebKit/Source/web/WebLocalFrameImpl.cpp

Index: third_party/WebKit/Source/web/WebLocalFrameImpl.cpp
diff --git a/third_party/WebKit/Source/web/WebLocalFrameImpl.cpp b/third_party/WebKit/Source/web/WebLocalFrameImpl.cpp
index fa8680ad832bbe4e3bc47c0a3548e81272aec089..5aacfaf190477d6be7be87eebfb48a5eb5d5ef23 100644
--- a/third_party/WebKit/Source/web/WebLocalFrameImpl.cpp
+++ b/third_party/WebKit/Source/web/WebLocalFrameImpl.cpp
@@ -2059,6 +2059,19 @@ void WebLocalFrameImpl::loadData(const WebData& data,
       static_cast<HistoryLoadType>(webHistoryLoadType));
 }
 
+bool WebLocalFrameImpl::canRenderFallbackContent() const {
+  DCHECK(frame());
+  return frame()->owner() && frame()->owner()->canRenderFallbackContent();
+}
+
+void WebLocalFrameImpl::loadFailed() {
+  DCHECK(frame());
+  if (frame()->owner())
+    frame()->owner()->renderFallbackContent();

[Nate Chapin, 2016/10/27 16:44:02]

Sorry, I was suggesting, instead of calling renderFallbackContent() here, have
this function call:

frame()->loader().loadFailed();

Is that sufficient?

If we do that, we may also be able to get rid of some of the logic in
RenderFrameImpl::OnFailedNavigation, which looks redundant with other load
failure logic.

+
+  stopLoading();
+}
+
 bool WebLocalFrameImpl::isLoading() const {
   if (!frame() || !frame()->document())
     return false;