Allow app banners to be triggered by increases in site engagement.

chrome/browser/banners/app_banner_manager.h

Index: chrome/browser/banners/app_banner_manager.h
diff --git a/chrome/browser/banners/app_banner_manager.h b/chrome/browser/banners/app_banner_manager.h
index f29c0bdbe89d583143d4ae604529d2f111d7d3e8..4b8ff1245be83094f44bb76c9b475ee6e2111be3 100644
--- a/chrome/browser/banners/app_banner_manager.h
+++ b/chrome/browser/banners/app_banner_manager.h
@@ -11,6 +11,7 @@
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "chrome/browser/banners/app_banner_data_fetcher.h"
+#include "chrome/browser/engagement/site_engagement_observer.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "third_party/WebKit/public/platform/modules/app_banner/WebAppBannerPromptReply.h"
 
@@ -30,7 +31,8 @@ class AppBannerDataFetcher;
  * requested app. Any work in progress for other apps is discarded.
  */
 class AppBannerManager : public content::WebContentsObserver,
-                         public AppBannerDataFetcher::Delegate {
+                         public AppBannerDataFetcher::Delegate,
+                         public SiteEngagementObserver {
  public:
   static void DisableSecureSchemeCheckForTesting();
 
@@ -42,11 +44,8 @@ class AppBannerManager : public content::WebContentsObserver,
 
   // Requests an app banner. Set |is_debug_mode| when it is triggered by the
   // developer's action in DevTools.
-  void RequestAppBanner(content::RenderFrameHost* render_frame_host,
-                        const GURL& validated_url,
-                        bool is_debug_mode);
+  void RequestAppBanner(const GURL& validated_url, bool is_debug_mode);
 
-  AppBannerManager();
   ~AppBannerManager() override;
 
  protected:
@@ -73,18 +72,30 @@ class AppBannerManager : public content::WebContentsObserver,
   void DidFinishLoad(content::RenderFrameHost* render_frame_host,
                      const GURL& validated_url) override;
 
+  void WasShown() override;
+  void WasHidden() override;
+
   // AppBannerDataFetcher::Delegate overrides.
   bool HandleNonWebApp(const std::string& platform,
                        const GURL& url,
                        const std::string& id,
                        bool is_debug_mode) override;
 
+  // SiteEngagementObserver overrides.
+  void OnEngagementIncreased(const SiteEngagementService* service,
+                             const GURL& url,
+                             double score) override;
+
   // Cancels an active DataFetcher, stopping its banners from appearing.
   void CancelActiveFetcher();
 
   // The type of navigation made to the page
   ui::PageTransition last_transition_type_;
 
+  GURL validated_url_;
+
+  bool is_visible_;
+
   // Fetches the data required to display a banner for the current page.
   scoped_refptr<AppBannerDataFetcher> data_fetcher_;