Make the browser->metro_viewer IPC channel name a constant instead of hardcoding it in a few places…

chrome/browser/metro_viewer/chrome_metro_viewer_process_host_aurawin.cc

 // Copyright 2012 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/metro_viewer/chrome_metro_viewer_process_host_aurawin.h"
 
 #include "base/logging.h"
 #include "base/memory/ref_counted.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/browser_process_platform_part_aurawin.h"
@@ skipping 39 matching lines @@
   Browser* browser = chrome::FindOrCreateTabbedBrowser(
       ProfileManager::GetDefaultProfileOrOffTheRecord(),
       chrome::HOST_DESKTOP_TYPE_ASH);
   browser->OpenURL(content::OpenURLParams(
     GURL(url), content::Referrer(), NEW_FOREGROUND_TAB,
     content::PAGE_TRANSITION_TYPED, false));
 }
 
 }  // namespace
 
-ChromeMetroViewerProcessHost::ChromeMetroViewerProcessHost(
-    const std::string& ipc_channel_name)
-        : MetroViewerProcessHost(
-              ipc_channel_name,
-              content::BrowserThread::GetMessageLoopProxyForThread(
-                  content::BrowserThread::IO)) {
+ChromeMetroViewerProcessHost::ChromeMetroViewerProcessHost()
+    : MetroViewerProcessHost(
+          content::BrowserThread::GetMessageLoopProxyForThread(
+              content::BrowserThread::IO)) {
   g_browser_process->AddRefModule();
 }
 
 void  ChromeMetroViewerProcessHost::OnChannelError() {
   // TODO(cpu): At some point we only close the browser. Right now this
   // is very convenient for developing.
   DLOG(INFO) << "viewer channel error : Quitting browser";
   aura::RemoteRootWindowHostWin::Instance()->Disconnected();
   g_browser_process->ReleaseModule();
   CloseOpenAshBrowsers();
@@ skipping 36 matching lines @@
           ProfileManager::GetDefaultProfileOrOffTheRecord())->
               GetDefaultSearchProvider();
   if (default_provider) {
     const TemplateURLRef& search_url = default_provider->url_ref();
     DCHECK(search_url.SupportsReplacement());
     GURL request_url = GURL(search_url.ReplaceSearchTerms(
         TemplateURLRef::SearchTermsArgs(search_string)));
     OpenURL(request_url);
   }
 }