Introduce ManifestUpgradeDetector for WebAPK to detect web manifest changes.

chrome/browser/android/webapps/add_to_homescreen_data_fetcher.h

Index: chrome/browser/android/webapps/add_to_homescreen_data_fetcher.h
diff --git a/chrome/browser/android/webapps/add_to_homescreen_data_fetcher.h b/chrome/browser/android/webapps/add_to_homescreen_data_fetcher.h
index d02b94576e07aa3f981ee13c89db80f71d8d2554..d4fad1edbf4633e139bc874337f749dd86693176 100644
--- a/chrome/browser/android/webapps/add_to_homescreen_data_fetcher.h
+++ b/chrome/browser/android/webapps/add_to_homescreen_data_fetcher.h
@@ -38,6 +38,8 @@ class AddToHomescreenDataFetcher
  public:
   class Observer {
    public:
+    virtual void OnDidHasManifest(bool has_manifest) = 0;
+
     // Called when the title of the page is available.
     virtual void OnUserTitleAvailable(const base::string16& title) = 0;
 
@@ -50,7 +52,8 @@ class AddToHomescreenDataFetcher
 
     // Called when all the data needed to create a shortcut is available.
     virtual void OnDataAvailable(const ShortcutInfo& info,
-                                 const SkBitmap& icon) = 0;
+                                 const SkBitmap& icon,
+                                 const std::vector<std::string>& icon_urls) = 0;
   };
 
   // Initialize the fetcher by requesting the information about the page to the
@@ -61,8 +64,12 @@ class AddToHomescreenDataFetcher
                              int minimum_icon_size_in_dp,
                              int ideal_splash_image_size_in_dp,
                              int minimum_splash_image_size_in_dp,
+                             bool stop_fetch_when_no_manifest,
                              Observer* observer);
 
+  // Replaces the WebContents that is being observed.
+  void ReplaceWebContents(content::WebContents* web_contents);
+
   // Returns a callback which fetches the splash screen image to be stored for
   // the webapp with the specified |id|.
   base::Closure FetchSplashScreenImageCallback(const std::string& id);
@@ -70,6 +77,8 @@ class AddToHomescreenDataFetcher
   // IPC message received when the initialization is finished.
   void OnDidGetWebApplicationInfo(const WebApplicationInfo& web_app_info);
 
+  void OnDidHasManifest(bool has_manifest);
+
   // Called when the Manifest has been parsed, or if no Manifest was found.
   void OnDidGetManifest(const GURL& manifest_url,
                         const content::Manifest& manifest);
@@ -116,6 +125,7 @@ class AddToHomescreenDataFetcher
   ShortcutInfo shortcut_info_;
   GURL splash_screen_url_;
 
+  std::vector<std::string> icon_urls_;
   // The icon must only be set on the UI thread for thread safety.
   SkBitmap shortcut_icon_;
   base::CancelableTaskTracker favicon_task_tracker_;
@@ -125,6 +135,8 @@ class AddToHomescreenDataFetcher
   const int ideal_splash_image_size_in_dp_;
   const int minimum_splash_image_size_in_dp_;
 
+  const bool stop_fetch_when_no_manifest_;
+
   friend class base::RefCounted<AddToHomescreenDataFetcher>;
   DISALLOW_COPY_AND_ASSIGN(AddToHomescreenDataFetcher);
 };