Music in keyguard improvements

- fix overscroll issue with workaround described in bug 7137941
- ignore noisy signals from music player that sometimes hide it

Change-Id: I6a25674ce7157bd70409f56881ec62644f5fce9b

Author: Jim Miller

core/res/res/layout/keyguard_transport_control_view.xml

@@ -20,6 +20,7 @@
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:gravity="center_horizontal"
+    android:layerType="hardware"
     android:id="@+id/keyguard_transport_control">
 
     <!-- FrameLayout used as scrim to show between album art and buttons -->

policy/src/com/android/internal/policy/impl/keyguard/KeyguardHostView.java

@@ -142,10 +142,11 @@ protected void onFinishInflate() {
                 (KeyguardTransportControlView) findViewById(R.id.keyguard_transport_control);
         if (mTransportControl != null) {
             mTransportControl.setKeyguardCallback(new TransportCallback() {
+                boolean mSticky = false;
                 @Override
                 public void hide() {
                     int page = getWidgetPosition(R.id.keyguard_transport_control);
-                    if (page != -1) {
+                    if (page != -1 && !mSticky) {
                         if (page == mAppWidgetContainer.getCurrentPage()) {
                             // Switch back to clock view if music was showing.
                             mAppWidgetContainer
@@ -166,6 +167,8 @@ public void show() {
                         mAppWidgetContainer.addView(mTransportControl,
                                 getWidgetPosition(R.id.keyguard_status_view) + 1);
                         mTransportControl.setVisibility(View.VISIBLE);
+                        // Once shown, leave it showing
+                        mSticky = true;
                     }
                 }
             });