Fixing lock during RecentsModel initialization

HandlerThread.getLooper blocks the current thread until.
the final thread is initialized. Updating RecentsModel to
use an executor instead of a handler thread to avoid this.

Change-Id: I3b2e82a375ea65bea1526af4a32c6a2488102541

quickstep/src/com/android/quickstep/OverviewCommandHelper.java

@@ -47,7 +47,6 @@ public class OverviewCommandHelper {
 
     private final Context mContext;
     private final RecentsAnimationDeviceState mDeviceState;
-    private final RecentsModel mRecentsModel;
     private final OverviewComponentObserver mOverviewComponentObserver;
 
     private long mLastToggleTime;
@@ -56,7 +55,6 @@ public class OverviewCommandHelper {
             OverviewComponentObserver observer) {
         mContext = context;
         mDeviceState = deviceState;
-        mRecentsModel = RecentsModel.INSTANCE.get(mContext);
         mOverviewComponentObserver = observer;
     }
 
@@ -160,7 +158,7 @@ public class OverviewCommandHelper {
                     ActivityManagerWrapper.getInstance().getRunningTask(), mDeviceState);
 
             // Preload the plan
-            mRecentsModel.getTasks(null);
+            RecentsModel.INSTANCE.get(mContext).getTasks(null);
         }
 
         @Override