Implement experimental app banner flow.

chrome/browser/banners/app_banner_manager.h

 // Copyright 2015 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_BANNERS_APP_BANNER_MANAGER_H_
 #define CHROME_BROWSER_BANNERS_APP_BANNER_MANAGER_H_
 
 #include <vector>
 
 #include "base/macros.h"
@@ skipping 233 matching lines @@
   // The referrer string (if any) specified in the app URL. Used only for native
   // app banners.
   std::string referrer_;
 
   // The current banner pipeline state for this page load.
   State state_;
 
  private:
   friend class AppBannerManagerTest;
 
+  // Returns whether the new experimental flow and UI is enabled.
+  static bool IsExperimentalAppBannersEnabled();
+
   // Record that the banner could be shown at this point, if the triggering
   // heuristic allowed.
   void RecordCouldShowBanner();
 
-  // Creates a banner for the app. Overridden by subclasses as the infobar is
+  // Creates the app banner UI. Overridden by subclasses as the infobar is
   // platform-specific.
-  virtual void ShowBanner() = 0;
+  virtual void ShowBannerUI() = 0;
 
   // Called after the manager sends a message to the renderer regarding its
   // intention to show a prompt. The renderer will send a message back with the
   // opportunity to cancel.
   void OnBannerPromptReply(blink::mojom::AppBannerPromptReply reply,
                            const std::string& referrer);
 
+  // Does the non-platform specific parts of showing the app banner.
+  void ShowBanner();
+
   // blink::mojom::AppBannerService overrides.
   // Called when Blink has prevented a banner from being shown, and is now
   // requesting that it be shown later.
   void DisplayAppBanner(bool user_gesture) override;
 
   // Fetches the data required to display a banner for the current page.
   InstallableManager* manager_;
 
   // A monotonically increasing id to verify the response to the
   // beforeinstallprompt event from the renderer.
@@ skipping 27 matching lines @@
   // scoped to the WebContents which they are observing. This allows us to use
   // weak pointers for callbacks.
   base::WeakPtrFactory<AppBannerManager> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(AppBannerManager);
 };
 
 }  // namespace banners
 
 #endif  // CHROME_BROWSER_BANNERS_APP_BANNER_MANAGER_H_