PlzNavigate: fix timing issue in app window creation

extensions/browser/app_window/app_window_contents.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "extensions/browser/app_window/app_window_contents.h"
 
 #include <string>
 #include <utility>
 
 #include "content/public/browser/browser_context.h"
@@ skipping 100 matching lines @@
 bool AppWindowContentsImpl::OnMessageReceived(const IPC::Message& message) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(AppWindowContentsImpl, message)
     IPC_MESSAGE_HANDLER(ExtensionHostMsg_UpdateDraggableRegions,
                         UpdateDraggableRegions)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
 }
 
+void AppWindowContentsImpl::ReadyToCommitNavigation(
+    content::NavigationHandle* handle) {
+  if (is_window_ready_)
+    return;
+  host_->OnReadyToCommit();

[Devlin, 2015/09/16 21:44:04]

OnReadyToCommit() implies it might be called on *every* commit.  Maybe include a
"first" somewhere?

[clamy, 2015/09/16 22:19:39]

Done.

+}
+
 void AppWindowContentsImpl::UpdateDraggableRegions(
     const std::vector<DraggableRegion>& regions) {
   host_->UpdateDraggableRegions(regions);
 }
 
 void AppWindowContentsImpl::SuspendRenderFrameHost(
     content::RenderFrameHost* rfh) {
   DCHECK(rfh);
   // Don't bother blocking requests if the renderer side is already good to go.
   if (is_window_ready_)
     return;
   is_blocking_requests_ = true;
   // The ResourceDispatcherHost only accepts RenderViewHost child ids.
   // TODO(devlin): This will need to change for site isolation.
   content::BrowserThread::PostTask(
       content::BrowserThread::IO, FROM_HERE,
       base::Bind(&content::ResourceDispatcherHost::BlockRequestsForRoute,
                  base::Unretained(content::ResourceDispatcherHost::Get()),
                  rfh->GetProcess()->GetID(),
                  rfh->GetRenderViewHost()->GetRoutingID()));
 }
 
 }  // namespace extensions