Expose manual playback control hiding from SimpleExoPlayerView

Issue #2146

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=141036866

library/src/main/java/com/google/android/exoplayer2/ui/SimpleExoPlayerView.java

@@ -398,6 +398,15 @@ public final class SimpleExoPlayerView extends FrameLayout {
   }
 
   /**
+   * Hides the playback controls. Does nothing if playback controls are disabled.
+   */
+  public void hideController() {
+    if (controller != null) {
+      controller.hide();
+    }
+  }
+
+  /**
    * Returns the playback controls timeout. The playback controls are automatically hidden after
    * this duration of time has elapsed without user input and with playback or buffering in
    * progress.
@@ -583,12 +592,6 @@ public final class SimpleExoPlayerView extends FrameLayout {
     }
   }
 
-  private void hideController() {
-    if (controller != null) {
-      controller.hide();
-    }
-  }
-
   @SuppressWarnings("ResourceType")
   private static void setResizeModeRaw(AspectRatioFrameLayout aspectRatioFrame, int resizeMode) {
     aspectRatioFrame.setResizeMode(resizeMode);