[App banners] Add server-controlled experiment to disable app banners

chrome/browser/android/banners/app_banner_manager.h

 // 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.
 
 #ifndef CHROME_BROWSER_ANDROID_BANNERS_APP_BANNER_MANAGER_H_
 #define CHROME_BROWSER_ANDROID_BANNERS_APP_BANNER_MANAGER_H_
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_weak_ref.h"
 #include "base/memory/ref_counted.h"
@@ skipping 95 matching lines @@
   // Record that the banner could be shown at this point, if the triggering
   // heuristic allowed.
   void RecordCouldShowBanner(const std::string& package_or_start_url);
 
   // Check if the banner should be shown.
   bool CheckIfShouldShow(const std::string& package_or_start_url);
 
   // Cancels an active BitmapFetcher, stopping its banner from appearing.
   void CancelActiveFetcher();
 
+  // Whether or not the banners should appear for native apps.
+  static bool IsEnabledForNativeApps();
+
   // Icon size that we want to be use for the launcher.
   const int preferred_icon_size_;
 
   // Fetches the icon for an app.  Weakly held because they delete themselves.
   BannerBitmapFetcher* fetcher_;
 
   GURL validated_url_;
   GURL app_icon_url_;
 
   base::string16 app_title_;
@@ skipping 13 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(AppBannerManager);
 };  // class AppBannerManager
 
 // Register native methods
 bool RegisterAppBannerManager(JNIEnv* env);
 
 }  // namespace banners
 
 #endif  // CHROME_BROWSER_ANDROID_BANNERS_APP_BANNER_MANAGER_H_