Add new UI package.

There aren't really enough classes to justify it right
now, but if we're going to do a VideoView equivalent and
sensible player controls at some point, it's worth making
now to get classes into the correct place.
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=127184374

demo/src/main/java/com/google/android/exoplayer2/demo/PlayerActivity.java

@@ -15,7 +15,6 @@
  */
 package com.google.android.exoplayer2.demo;
 
-import com.google.android.exoplayer2.AspectRatioFrameLayout;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.DefaultLoadControl;
 import com.google.android.exoplayer2.DefaultTrackSelectionPolicy;
@@ -47,11 +46,12 @@ import com.google.android.exoplayer2.source.smoothstreaming.SmoothStreamingMedia
 import com.google.android.exoplayer2.text.CaptionStyleCompat;
 import com.google.android.exoplayer2.text.Cue;
 import com.google.android.exoplayer2.text.SubtitleLayout;
+import com.google.android.exoplayer2.ui.AspectRatioFrameLayout;
+import com.google.android.exoplayer2.ui.PlayerControl;
 import com.google.android.exoplayer2.upstream.BandwidthMeter;
 import com.google.android.exoplayer2.upstream.DataSourceFactory;
 import com.google.android.exoplayer2.upstream.DefaultDataSourceFactory;
 import com.google.android.exoplayer2.util.DebugTextViewHelper;
-import com.google.android.exoplayer2.util.PlayerControl;
 import com.google.android.exoplayer2.util.Util;
 
 import android.Manifest.permission;

demo/src/main/res/layout/player_activity.xml

@@ -21,7 +21,8 @@
     android:layout_height="match_parent"
     android:keepScreenOn="true">
 
-  <com.google.android.exoplayer2.AspectRatioFrameLayout android:id="@+id/video_frame"
+  <com.google.android.exoplayer2.ui.AspectRatioFrameLayout
+      android:id="@+id/video_frame"
       android:layout_width="match_parent"
       android:layout_height="match_parent"
       android:layout_gravity="center">
@@ -40,7 +41,7 @@
         android:layout_width="match_parent"
         android:layout_height="match_parent"/>
 
-  </com.google.android.exoplayer2.AspectRatioFrameLayout>
+  </com.google.android.exoplayer2.ui.AspectRatioFrameLayout>
 
   <LinearLayout
       android:layout_width="match_parent"

library/src/main/java/com/google/android/exoplayer2/AspectRatioFrameLayout.java → library/src/main/java/com/google/android/exoplayer2/ui/AspectRatioFrameLayout.java

@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.google.android.exoplayer2;
+package com.google.android.exoplayer2.ui;
 
 import android.content.Context;
 import android.util.AttributeSet;

library/src/main/java/com/google/android/exoplayer2/util/PlayerControl.java → library/src/main/java/com/google/android/exoplayer2/ui/PlayerControl.java

@@ -13,10 +13,11 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.google.android.exoplayer2.util;
+package com.google.android.exoplayer2.ui;
 
 import com.google.android.exoplayer2.ExoPlayer;
 import com.google.android.exoplayer2.MediaCodecAudioRenderer;
+import com.google.android.exoplayer2.util.Util;
 
 import android.widget.MediaController.MediaPlayerControl;