Merge "Check if mGrContext exists when requiring a vk context."

void RenderThread::requireVkContext() {

    // the getter creates the context in the event it had been destroyed by destroyRenderingContext

    if (vulkanManager().hasVkContext()) {

    // Also check if we have a GrContext before returning fast. VulkanManager may be shared with

    // the HardwareBitmapUploader which initializes the Vk context without persisting the GrContext

    // in the rendering thread.

    if (vulkanManager().hasVkContext() && mGrContext) {

        return;

    }

    mVkManager->initialize();