Merge "Make ConsumerProxy hold weak ref to GraphicBufferSource" into qt-dev

};

struct GraphicBufferSource::ConsumerProxy : public BufferQueue::ConsumerListener {

    ConsumerProxy(const sp<GraphicBufferSource> &gbs) : mGbs(gbs) {}

    ConsumerProxy(const wp<GraphicBufferSource> &gbs) : mGbs(gbs) {}

    ~ConsumerProxy() = default;

    void onFrameAvailable(const BufferItem& item) override {

        mGbs->onFrameAvailable(item);

        sp<GraphicBufferSource> gbs = mGbs.promote();

        if (gbs != nullptr) {

            gbs->onFrameAvailable(item);

        }

    }

    void onBuffersReleased() override {

        mGbs->onBuffersReleased();

        sp<GraphicBufferSource> gbs = mGbs.promote();

        if (gbs != nullptr) {

            gbs->onBuffersReleased();

        }

    }

    void onSidebandStreamChanged() override {

        mGbs->onSidebandStreamChanged();

        sp<GraphicBufferSource> gbs = mGbs.promote();

        if (gbs != nullptr) {

            gbs->onSidebandStreamChanged();

        }

    }

private:

    sp<GraphicBufferSource> mGbs;

    // Note that GraphicBufferSource is holding an sp to us, we can't hold

    // an sp back to GraphicBufferSource as the circular dependency will

    // make both immortal.

    wp<GraphicBufferSource> mGbs;

};

GraphicBufferSource::GraphicBufferSource() :