Fixing issue where defered unbind was running after synchronous bind. (Bug 6858398, Bug 6863181)

Change-Id: I03dc3ae18528901cc88c79638a8495c1ab8d61af

src/com/android/launcher2/DeferredHandler.java

@@ -98,6 +98,18 @@ public class DeferredHandler {
         }
     }
 
+    /** Runs all queued Runnables from the calling thread. */
+    public void flush() {
+        LinkedList<Runnable> queue = new LinkedList<Runnable>();
+        synchronized (mQueue) {
+            queue.addAll(mQueue);
+            mQueue.clear();
+        }
+        for (Runnable r : queue) {
+            r.run();
+        }
+    }
+
     void scheduleNextLocked() {
         if (mQueue.size() > 0) {
             Runnable peek = mQueue.getFirst();

src/com/android/launcher2/LauncherModel.java

@@ -918,6 +918,11 @@ public class LauncherModel extends BroadcastReceiver {
             //      data structures, we can't allow any other thread to touch that data, but because
             //      this call is synchronous, we can get away with not locking).
 
+            // The LauncherModel is static in the LauncherApplication and mHandler may have queued
+            // operations from the previous activity.  We need to ensure that all queued operations
+            // are executed before any synchronous binding work is done.
+            mHandler.flush();
+
             // Divide the set of loaded items into those that we are binding synchronously, and
             // everything else that is to be bound normally (asynchronously).
             bindWorkspace(synchronousBindPage);