[Remoting Android] JniGlDisplayHandler calls invalidate() on UI thread

remoting/android/java/src/org/chromium/chromoting/jni/GlDisplay.java

Index: remoting/android/java/src/org/chromium/chromoting/jni/GlDisplay.java
diff --git a/remoting/android/java/src/org/chromium/chromoting/jni/GlDisplay.java b/remoting/android/java/src/org/chromium/chromoting/jni/GlDisplay.java
index dedbbb4e0361a6c33121c0b22a15f8cd5dc2cdb8..30281d5768401adbae8390b2f2f9818f83ebca3f 100644
--- a/remoting/android/java/src/org/chromium/chromoting/jni/GlDisplay.java
+++ b/remoting/android/java/src/org/chromium/chromoting/jni/GlDisplay.java
@@ -26,11 +26,11 @@ import org.chromium.chromoting.SizeChangedEventParameter;
  *
  * This class works entirely on the UI thread:
  *  Functions should all be called on UI.
- *  Events will only be triggered on UI.
+ *  Callbacks by native counterpart are called on UI.
  */
 @JNINamespace("remoting")
 public class GlDisplay implements SurfaceHolder.Callback, RenderStub {
-    private volatile long mNativeJniGlDisplay;
+    private long mNativeJniGlDisplay;
     private final Event.Raisable<SizeChangedEventParameter> mOnClientSizeChanged =
             new Event.Raisable<>();
     private final Event.Raisable<SizeChangedEventParameter> mOnHostSizeChanged =
@@ -45,8 +45,7 @@ public class GlDisplay implements SurfaceHolder.Callback, RenderStub {
     }
 
     /**
-     * Invalidates this object and disconnects from the native display handler. Called on the
-     * display thread by the native code.
+     * Invalidates this object and disconnects from the native display handler.
      */
     @CalledByNative
     private void invalidate() {