Now closes existing background contents if app opens a new one.

chrome/browser/tab_contents/render_view_host_delegate_helper.cc

 // Copyright (c) 2011 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/tab_contents/render_view_host_delegate_helper.h"
 
 #include <string>
 
 #include "base/command_line.h"
 #include "base/string_util.h"
@@ skipping 89 matching lines @@
   const Extension* extension =
       extensions_service->GetExtensionByWebExtent(opener_url);
   if (!extension)
     return NULL;
 
   // If the extension manifest specifies a background page, then don't allow one
   // to be created here.
   if (extension->background_url().is_valid())
     return NULL;
 
-  // Only allow a single background contents per app.
+  // No BackgroundContents allowed if BackgroundContentsService doesn't exist.
   BackgroundContentsService* service =
       BackgroundContentsServiceFactory::GetForProfile(profile);
-  if (!service || service->GetAppBackgroundContents(
-          ASCIIToUTF16(extension->id())))
+  if (!service)
     return NULL;
 
   // Ensure that we're trying to open this from the extension's process.
   ExtensionProcessManager* process_manager =
       profile->GetExtensionProcessManager();
   if (!site->GetProcess() || !process_manager ||
       site->GetProcess() != process_manager->GetExtensionProcess(opener_url))
     return NULL;
 
+  // Only allow a single background contents per app. If one already exists,
+  // close it.
+  BackgroundContents* existing =
+      service->GetAppBackgroundContents(ASCIIToUTF16(extension->id()));
+  if (existing) {
+    DLOG(WARNING) << "Closing existing BackgroundContents for " << opener_url;
+    existing->render_view_host()->ClosePage();
+    delete existing;
+  }
+
   // Passed all the checks, so this should be created as a BackgroundContents.
   return service->CreateBackgroundContents(site, route_id, profile, frame_name,
                                            ASCIIToUTF16(extension->id()));
 }
 
 TabContents* RenderViewHostDelegateViewHelper::CreateNewWindow(
     int route_id,
     Profile* profile,
     SiteInstance* site,
     WebUI::TypeID webui_type,
@@ skipping 400 matching lines @@
   DictionaryValue* inspector_settings = update.Get();
   inspector_settings->SetWithoutPathExpansion(key,
                                               Value::CreateStringValue(value));
 }
 
 void RenderViewHostDelegateHelper::ClearInspectorSettings(
     content::BrowserContext* browser_context) {
   Profile::FromBrowserContext(browser_context)->GetPrefs()->
       ClearPref(prefs::kWebKitInspectorSettings);
 }