Remove unused member in VulkanManager.

    void initialize();

    // Quick check to see if the VulkanManager has been initialized.

    bool hasVkContext() { return mBackendContext.get() != nullptr; }

    bool hasVkContext() { return mDevice != VK_NULL_HANDLE; }

    // Given a window this creates a new VkSurfaceKHR and VkSwapchain and stores them inside a new

    // VulkanSurface object which is returned.

    RenderThread& mRenderThread;

    sk_sp<const GrVkBackendContext> mBackendContext;

    VkInstance mInstance = VK_NULL_HANDLE;

    VkPhysicalDevice mPhysicalDevice = VK_NULL_HANDLE;

    VkDevice mDevice = VK_NULL_HANDLE;