Refactor ShortcutHelper (Java/C++) to allow asynchronous init.

chrome/android/java/src/org/chromium/chrome/browser/ShortcutHelper.java

Index: chrome/android/java/src/org/chromium/chrome/browser/ShortcutHelper.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/ShortcutHelper.java b/chrome/android/java/src/org/chromium/chrome/browser/ShortcutHelper.java
index 9762af96c1a8ccab4b72e70771067bab3da9eda8..e2778838229bfc5ec9d9e82a6c762e93561f3bb1 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/ShortcutHelper.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/ShortcutHelper.java
@@ -38,19 +38,79 @@ public class ShortcutHelper {
     }
 
     /**
+     * Callback to be passed to the initialized() method.
+     */
+    public interface OnInitialized {
+        public void onInitialized(String title);
+    }
+
+    private OnInitialized mCallback = null;

[gone, 2014/09/11 18:24:36]

these are all initialized by default to the values you set.  don't need to make
them explicit.

[mlamouri (slow - plz ping), 2014/09/11 19:31:02]

I actually prefer explicit init but I've updated this.

[gone, 2014/09/11 20:32:21]

Eh, AFAIK it's been the standard to not define these if they are meant to have
the default value, at least in the downstream tree.  Can't see it in the Android
style guide though, so maybe it's just convention.

+    private Context mAppContext = null;
+    private Tab mTab = null;

[gone, 2014/09/11 18:24:36]

private final Context mAppContext;
private final Tab mTab;

move above regular private fields

[mlamouri (slow - plz ping), 2014/09/11 19:31:02]

Done.

+    private boolean mInitialized = false;

[gone, 2014/09/11 18:24:36]

nit: private boolean mIsInitialized;

[mlamouri (slow - plz ping), 2014/09/11 19:31:02]

Done.

+    private long mNativeShortcutHelper = 0;
+
+    public ShortcutHelper(Context appContext, Tab tab) {
+        mAppContext = appContext;
+        mTab = tab;
+    }
+
+    /**
+     * Gets all the information required to initialize the UI, the passed
+     * callback will be run when those information will be available.
+     * @param callback Callback to be run when initialized.
+     */
+    public void initialize(OnInitialized callback) {
+        mCallback = callback;
+        mNativeShortcutHelper = nativeInitialize(mTab.getNativePtr());
+    }
+
+    /**
+     * Returns whether the object is initialized.
+     */
+    public boolean initialized() {

[gone, 2014/09/11 18:24:36]

isInitialized()

[mlamouri (slow - plz ping), 2014/09/11 19:31:02]

Done.

+        return mInitialized;
+    }
+
+    /**
+     * Puts the object in a state where it is safe to be destroyed.
+     */
+    public void tearDown() {
+        nativeTearDown(mNativeShortcutHelper);
+
+        // Make sure the callback isn't run if the tear down happens before
+        // onInitialized() is called.
+        mCallback = null;
+        mNativeShortcutHelper = 0;
+    }
+
+    @CalledByNative
+    private void onInitialized(String title) {
+        mInitialized = true;
+
+        if (mCallback == null) {

[gone, 2014/09/11 18:24:36]

just make this:

if (mCallback != null) mCallback.onInitialized(title);

[mlamouri (slow - plz ping), 2014/09/11 19:31:02]

Done.

+            return;
+        }
+
+        mCallback.onInitialized(title);
+    }
+
+    /**
      * Adds a shortcut for the current Tab.
-     * @param appContext The application context.
-     * @param tab Tab to create a shortcut for.
      * @param userRequestedTitle Updated title for the shortcut.
      */
-    public static void addShortcut(Context appContext, Tab tab, String userRequestedTitle) {
+    public void addShortcut(String userRequestedTitle) {
         if (TextUtils.isEmpty(sFullScreenAction)) {
             Log.e("ShortcutHelper", "ShortcutHelper is uninitialized.  Aborting.");
             return;
         }
-        ActivityManager am = (ActivityManager) appContext.getSystemService(
+        ActivityManager am = (ActivityManager) mAppContext.getSystemService(
                 Context.ACTIVITY_SERVICE);
-        nativeAddShortcut(tab.getNativePtr(), userRequestedTitle, am.getLauncherLargeIconSize());
+        nativeAddShortcut(mNativeShortcutHelper, userRequestedTitle, am.getLauncherLargeIconSize());
+
+        // The C++ instance is no longer owned by the Java object.
+        mCallback = null;
+        mNativeShortcutHelper = 0;
     }
 
     /**
@@ -106,6 +166,8 @@ public class ShortcutHelper {
         context.startActivity(homeIntent);
     }
 
-    private static native void nativeAddShortcut(long tabAndroidPtr, String userRequestedTitle,
+    private native long nativeInitialize(long tabAndroidPtr);
+    private native void nativeAddShortcut(long nativeShortcutHelper, String userRequestedTitle,
             int launcherLargeIconSize);
+    private native void nativeTearDown(long nativeShortcutHelper);
 }