Update WebAPK if homescreen icon changed.

chrome/browser/android/shortcut_helper.h

Index: chrome/browser/android/shortcut_helper.h
diff --git a/chrome/browser/android/shortcut_helper.h b/chrome/browser/android/shortcut_helper.h
index f24995dffcb498b862b1253665a6b640d85dce9a..db26a583fb929ca2657ad07a0e3069544187854c 100644
--- a/chrome/browser/android/shortcut_helper.h
+++ b/chrome/browser/android/shortcut_helper.h
@@ -84,6 +84,12 @@ class ShortcutHelper {
   // screen.
   static int GetMinimumSplashImageSizeInDp();
 
+  // Called when the homescreen image fetch initiated in FetchHomescreenImage()
+  // completes.
+  static void OnFetchedHomescreenImage(
+      const base::android::ScopedJavaGlobalRef<jobject> java_callback,
+      const SkBitmap& image);
+
   // Fetches the splash screen image and stores it inside the WebappDataStorage
   // of the webapp. The WebappDataStorage object *must* have been previously
   // created by |AddShortcutInBackgroundWithSkBitmap|; this method should be