Pass the starting touch point in the DRAG_STARTED message

        /* call out to each visible window/session informing it about the drag

         */

        void broadcastDragStartedLw() {

        void broadcastDragStartedLw(final float touchX, final float touchY) {

            // Cache a base-class instance of the clip metadata so that parceling

            // works correctly in calling out to the apps.

            mDataDescription = new ClipDescription(mData);

            mNotifiedWindows.clear();

            mDragInProgress = true;

            DragEvent evt = DragEvent.obtain(DragEvent.ACTION_DRAG_STARTED, touchX, touchY,

                    mDataDescription, null);

            if (DEBUG_DRAG) {

                Slog.d(TAG, "broadcasting DRAG_STARTED of " + mDataDescription);

                Slog.d(TAG, "broadcasting DRAG_STARTED: " + evt);

            }

            DragEvent evt = DragEvent.obtain(DragEvent.ACTION_DRAG_STARTED, 0, 0,

                    mDataDescription, null);

            final int N = mWindows.size();

            for (int i = 0; i < N; i++) {

                // sendDragStartedLw() clones evt for local-process dispatch

                        mDragState.mServerChannel);

                mDragState.mData = data;

                mDragState.broadcastDragStartedLw();

                mDragState.broadcastDragStartedLw(touchX, touchY);

                // remember the thumb offsets for later

                mDragState.mThumbOffsetX = thumbCenterX;