Merge "Protect a11y against multi-threaded UIs"

        @Override

        public void run() {

            // mSource may be changed in calls below.

            // Protect against re-entrant code and attempt to do the right thing in the case that

            // we're multithreaded.

            View source = mSource;

            mSource = null;

            if (source == null) {

                Log.e(TAG, "Accessibility content change has no source");

                return;

            }

            // The accessibility may be turned off while we were waiting so check again.

            if (AccessibilityManager.getInstance(mContext).isEnabled()) {

                mLastEventTimeMillis = SystemClock.uptimeMillis();

        }

        public void runOrPost(View source, int changeType) {

            if (mHandler.getLooper() != Looper.myLooper()) {

                CalledFromWrongThreadException e = new CalledFromWrongThreadException("Only the "

                        + "original thread that created a view hierarchy can touch its views.");

                // TODO: Throw the exception

                Log.e(TAG, "Accessibility content change on non-UI thread. Future Android "

                        + "versions will throw an exception.", e);

                // Attempt to recover. This code does not eliminate the thread safety issue, but

                // it should force any issues to happen near the above log.

                mHandler.removeCallbacks(this);

                if (mSource != null) {

                    // Dispatch whatever was pending. It's still possible that the runnable started

                    // just before we removed the callbacks, and bad things will happen, but at

                    // least they should happen very close to the logged error.

                    run();

                }

            }

            if (mSource != null) {

                // If there is no common predecessor, then mSource points to

                // a removed view, hence in this case always prefer the source.

            if (timeSinceLastMillis >= minEventIntevalMillis) {

                removeCallbacksAndRun();

            } else {

                mSource.postDelayed(this, minEventIntevalMillis - timeSinceLastMillis);

                mHandler.postDelayed(this, minEventIntevalMillis - timeSinceLastMillis);

            }

        }

        public void removeCallbacksAndRun() {

            mSource.removeCallbacks(this);

            mHandler.removeCallbacks(this);

            run();

        }

    }