Bug 856767: Finalize cursors on about:home. [r=mfinkle]

mobile/android/base/widget/AboutHomeContent.java

@@ -192,11 +192,12 @@ public class AboutHomeContent extends ScrollView
      * Reinflates and updates all components of this view.
      */
     public void refresh() {
+        mTopSites.onDestroy();
+
         // We must remove the currently inflated view to allow for reinflation.
         removeAllViews();
 
         inflate();
-        mTopSites.refresh();
 
         // Refresh all elements.
         update(AboutHomeContent.UpdateFlags.ALL);

mobile/android/base/widget/TopSitesView.java

@@ -141,9 +141,16 @@ public class TopSitesView extends GridView {
 
     public void onDestroy() {
         if (mTopSitesAdapter != null) {
-            Cursor cursor = mTopSitesAdapter.getCursor();
-            if (cursor != null && !cursor.isClosed())
-                cursor.close();
+            setAdapter(null);
+            final Cursor cursor = mTopSitesAdapter.getCursor();
+
+            ThreadUtils.postToBackgroundThread(new Runnable() {
+                @Override
+                public void run() {
+                if (cursor != null && !cursor.isClosed())
+                    cursor.close();
+                }
+            });
         }
     }
 
@@ -186,12 +193,9 @@ public class TopSitesView extends GridView {
 
     public void loadTopSites() {
         final ContentResolver resolver = mContext.getContentResolver();
-        Cursor old = null;
-        if (mTopSitesAdapter != null) {
-            old = mTopSitesAdapter.getCursor();
-        }
+
         // Swap in the new cursor.
-        final Cursor oldCursor = old;
+        final Cursor oldCursor = (mTopSitesAdapter != null) ? mTopSitesAdapter.getCursor() : null;
         final Cursor newCursor = BrowserDB.getTopSites(resolver, mNumberOfTopSites);
 
         post(new Runnable() {
@@ -340,13 +344,6 @@ public class TopSitesView extends GridView {
         mLoadCompleteCallback = callback;
     }
 
-    public void refresh() {
-        if (mTopSitesAdapter != null)
-            mTopSitesAdapter.notifyDataSetChanged();
-
-        setAdapter(mTopSitesAdapter);
-    }
-
     private class TopSitesViewHolder {
         public TextView titleView = null;
         public ImageView thumbnailView = null;