Use DCHECKs when observing only a single notification.

chrome/browser/renderer_context_menu/render_view_context_menu_browsertest_util.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 "chrome/browser/renderer_context_menu/render_view_context_menu_browsertest_util.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread_task_runner_handle.h"
@@ skipping 11 matching lines @@
                  content::NotificationService::AllSources());
 }
 
 ContextMenuNotificationObserver::~ContextMenuNotificationObserver() {
 }
 
 void ContextMenuNotificationObserver::Observe(
     int type,
     const content::NotificationSource& source,
     const content::NotificationDetails& details) {
-  switch (type) {
-    case chrome::NOTIFICATION_RENDER_VIEW_CONTEXT_MENU_SHOWN: {
-      RenderViewContextMenu* context_menu =
-          content::Source<RenderViewContextMenu>(source).ptr();
-      base::ThreadTaskRunnerHandle::Get()->PostTask(
-          FROM_HERE,
-          base::Bind(&ContextMenuNotificationObserver::ExecuteCommand,
-                     base::Unretained(this), context_menu));
-      break;
-    }
+  DCHECK_EQ(chrome::NOTIFICATION_RENDER_VIEW_CONTEXT_MENU_SHOWN, type);
 
-    default:
-      NOTREACHED();
-  }
+  RenderViewContextMenu* context_menu =
+      content::Source<RenderViewContextMenu>(source).ptr();
+  base::ThreadTaskRunnerHandle::Get()->PostTask(
+      FROM_HERE, base::Bind(&ContextMenuNotificationObserver::ExecuteCommand,
+                            base::Unretained(this), context_menu));
 }
 
 void ContextMenuNotificationObserver::ExecuteCommand(
     RenderViewContextMenu* context_menu) {
   context_menu->ExecuteCommand(command_to_execute_, 0);
   context_menu->Cancel();
 }
 
 ContextMenuWaiter::ContextMenuWaiter(const content::NotificationSource& source)
     : menu_visible_(false) {
@@ skipping 35 matching lines @@
 }
 
 content::ContextMenuParams& ContextMenuWaiter::params() {
   return params_;
 }
 
 void ContextMenuWaiter::Cancel(RenderViewContextMenu* context_menu) {
   params_ = context_menu->params();
   context_menu->Cancel();
 }