Merge "Release virtual display hwcId during vr mode transition." into oc-dev am: 5d6d98a1

    // mCurrentState and mDrawingState and re-apply all changes when we make the

    // transition.

    mDrawingState.displays.clear();

    // Release virtual display hwcId during vr mode transition.

    for (size_t displayId = 0; displayId < mDisplays.size(); ++displayId) {

        const sp<DisplayDevice>& displayDevice = mDisplays[displayId];

        if (displayDevice->getDisplayType() == DisplayDevice::DISPLAY_VIRTUAL) {

            displayDevice->disconnect(getHwComposer());

        }

    }

    mDisplays.clear();

    initializeDisplays();

}