webapps: initial addition of splash screen icon downloading

chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappDataStorage.java

Index: chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappDataStorage.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappDataStorage.java b/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappDataStorage.java
index 19e5a935d6b721306e3371fbc31881e8009aeb73..47968fa6cab096b696bd522848e1f0edca58a2a6 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappDataStorage.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappDataStorage.java
@@ -9,6 +9,7 @@ import android.content.SharedPreferences;
 import android.graphics.Bitmap;
 import android.os.AsyncTask;
 
+import org.chromium.base.VisibleForTesting;
 import org.chromium.chrome.browser.ShortcutHelper;
 
 /**
@@ -23,6 +24,8 @@ public class WebappDataStorage {
     static final String KEY_SPLASH_ICON = "splash_icon";
     static final String KEY_LAST_USED = "last_used";
 
+    private static Observer sObserver = new Observer();
+
     private final SharedPreferences mPreferences;
 
     /**
@@ -50,6 +53,14 @@ public class WebappDataStorage {
                 .getLastUsedTime(callback);
     }
 
+    /**
+     * Sets the observer to use.
+     */
+    @VisibleForTesting
+    public static void setObserverForTests(Observer observer) {
+        sObserver = observer;
+    }
+
     private WebappDataStorage(Context context, String webappId) {
         mPreferences = context.getSharedPreferences(
                 SHARED_PREFS_FILE_PREFIX + webappId, Context.MODE_PRIVATE);
@@ -70,6 +81,7 @@ public class WebappDataStorage {
      * @param splashScreenImage The image which should be shown on the splash screen of the webapp.
      */
     public void updateSplashScreenImage(Bitmap splashScreenImage) {
+        sObserver.onUpdateSplashScreenImage(splashScreenImage);

[gone, 2015/09/01 18:33:51]

Why not set sObserver to null and check if it's null here?  The standard thing
to do for observer classes (especially ones added only for unit tests) is to
make the Observer an Interface and null check the Observer.

[Lalit Maganti, 2015/09/01 19:45:52]

That's what I did initially when I wrote this CL but I decided to follow what
had been done in app banner. Guess I should have stuck with my intuition.

Done.

[gone, 2015/09/01 20:50:53]

Where exactly does AppBanner* code set an empty observer?  Curious to see the
reasoning why it's done there and whether it would apply in this case. 

         new UpdateTask(splashScreenImage).execute();
     }
 
@@ -108,6 +120,18 @@ public class WebappDataStorage {
         public void onDataRetrieved(T readObject);
     }
 
+    /**
+     * Observer used to check splash screen download in tests.
+     */

[gone, 2015/09/01 18:33:51]

* Don't bother saying it's for tests; it might be expanded in the future:
  "Observer used to monitor splash screen downloads."

* Make this an Interface.

[Lalit Maganti, 2015/09/01 19:45:52]

Done.

+    public static class Observer {
+
+      /**

[gone, 2015/09/01 18:33:51]

nit: indentation is off.

[Lalit Maganti, 2015/09/01 19:45:52]

Done.

+       * Called when a splash screen update is queued.
+       */
+        public void onUpdateSplashScreenImage(Bitmap image) {
+        }
+    }
+
     private final class BitmapFetchTask extends AsyncTask<Void, Void, Bitmap> {
 
         private final String mKey;