Fix jumping dock divider when dismissing/maximizng.

import android.content.Context;

import android.graphics.Rect;

import android.util.Slog;

import static android.app.ActivityManager.StackId.DOCKED_STACK_ID;

import static android.view.WindowManager.DOCKED_BOTTOM;

    private boolean mResizing;

    private WindowState mWindow;

    private final Rect mTmpRect = new Rect();

    private final Rect mLastRect = new Rect();

    DockedStackDividerController(Context context, DisplayContent displayContent) {

        mDisplayContent = displayContent;

        if (stack == null) {

            // Unfortunately we might end up with still having a divider, even though the underlying

            // stack was already removed. This is because we are on AM thread and the removal of the

            // divider was deferred to WM thread and hasn't happened yet.

            // divider was deferred to WM thread and hasn't happened yet. In that case let's just

            // keep putting it in the same place it was before the stack was removed to have

            // continuity and prevent it from jumping to the center. It will get hidden soon.

            frame.set(mLastRect);

            return;

        } else {

            stack.getBounds(mTmpRect);

        }

        int side = stack.getDockSide();

        stack.getBounds(mTmpRect);

        switch (side) {

            case DOCKED_LEFT:

                frame.set(mTmpRect.right - mDividerInsets, frame.top,

                        frame.right, mTmpRect.top + mDividerInsets);

                break;

        }

        mLastRect.set(frame);

    }

}