[Extensions] DCHECK that ExtensionFunctions respond (and only once)

chrome/browser/apps/app_window_interactive_uitest.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 "base/macros.h"
 #include "build/build_config.h"
 #include "chrome/browser/apps/app_browsertest_util.h"
 #include "chrome/browser/lifetime/application_lifetime.h"
 #include "chrome/browser/lifetime/keep_alive_registry.h"
 #include "chrome/browser/lifetime/keep_alive_types.h"
@@ skipping 331 matching lines @@
 
 void AppWindowInteractiveTest::TestOuterBoundsHelper(
     const std::string& frame_type) {
   ExtensionTestMessageListener launched_listener("Launched", true);
   const extensions::Extension* app =
       LoadAndLaunchPlatformApp("outer_bounds", &launched_listener);
 
   launched_listener.Reply(frame_type);
   launched_listener.Reset();
   ASSERT_TRUE(launched_listener.WaitUntilSatisfied());
+  launched_listener.Reply(std::string());
 
   AppWindow* window = GetFirstAppWindowForApp(app->id());
   gfx::Rect window_bounds;
   gfx::Size min_size, max_size;
 
 #if defined(OS_WIN)
   // Get the bounds from the HWND.
   HWND hwnd = views::HWNDForNativeWindow(window->GetNativeWindow());
   RECT rect;
   ::GetWindowRect(hwnd, &rect);
@@ skipping 199 matching lines @@
   ExtensionTestMessageListener shown_listener("Shown", false);
   launched_listener.Reply("");
   EXPECT_TRUE(shown_listener.WaitUntilSatisfied());
   EXPECT_FALSE(app_window->is_hidden());
   EXPECT_TRUE(KeepAliveRegistry::GetInstance()->IsOriginRegistered(
       KeepAliveOrigin::CHROME_APP_DELEGATE));
   app_window->GetBaseWindow()->Close();
 }
 
 #endif