PlzNavigate: fix timing issue in app window creation

extensions/browser/app_window/app_window.cc

 // Copyright 2014 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.h"
 
 #include <algorithm>
 #include <string>
 #include <vector>
 
+#include "base/callback_helpers.h"
 #include "base/command_line.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/task_runner.h"
+#include "base/thread_task_runner_handle.h"
 #include "base/values.h"
 #include "components/web_modal/web_contents_modal_dialog_manager.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/invalidate_type.h"
 #include "content/public/browser/navigation_entry.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/resource_dispatcher_host.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/media_stream_request.h"
@@ skipping 411 matching lines @@
 
 void AppWindow::DidFirstVisuallyNonEmptyPaint() {
   first_paint_complete_ = true;
   if (show_on_first_paint_) {
     DCHECK(delayed_show_type_ == SHOW_ACTIVE ||
            delayed_show_type_ == SHOW_INACTIVE);
     Show(delayed_show_type_);
   }
 }
 
+void AppWindow::SetOnFirstCommitCallback(const base::Closure& callback) {
+  DCHECK(on_first_commit_callback_.is_null());
+  on_first_commit_callback_ = callback;
+}
+
+void AppWindow::OnReadyToCommitFirstNavigation() {
+  CHECK(base::CommandLine::ForCurrentProcess()->HasSwitch(
+      ::switches::kEnableBrowserSideNavigation));
+  WindowEventsReady();
+  if (on_first_commit_callback_.is_null())
+    return;
+  // It is important that the callback executes after the calls to
+  // WebContentsObserver::ReadyToCommitNavigation have been processed. The
+  // CommitNavigation IPC that will properly set up the renderer will only be
+  // sent after these, and it must be sent before the callback gets to run,
+  // hence the use of PostTask.
+  base::ThreadTaskRunnerHandle::Get()->PostTask(
+      FROM_HERE, base::ResetAndReturn(&on_first_commit_callback_));
+}
+
 void AppWindow::OnNativeClose() {
   AppWindowRegistry::Get(browser_context_)->RemoveAppWindow(this);
   if (app_window_contents_) {
     WebContentsModalDialogManager* modal_dialog_manager =
         WebContentsModalDialogManager::FromWebContents(web_contents());
     if (modal_dialog_manager)  // May be null in unit tests.
       modal_dialog_manager->SetDelegate(nullptr);
     app_window_contents_->NativeWindowClosed();
   }
   delete this;
@@ skipping 632 matching lines @@
         region.bounds.x(),
         region.bounds.y(),
         region.bounds.right(),
         region.bounds.bottom(),
         region.draggable ? SkRegion::kUnion_Op : SkRegion::kDifference_Op);
   }
   return sk_region;
 }
 
 }  // namespace extensions