SF: Make ExternalTexture mockable

Expose GraphicBuffer properties via ExternalTexture class. Within
SurfaceFlinger access the buffer via this proxy interface.
This allows us to inject and mock GraphicBuffers as needed.
Specifically this will be used to recreate layer state from
transaction traces.

Test: compiles
Bug: 200284593

Change-Id: I2e7f6bee28314b70eac477cfadbf9f94c4d70339
diff --git a/services/surfaceflinger/BufferStateLayer.h b/services/surfaceflinger/BufferStateLayer.h
index eea700c..2f613d7 100644
--- a/services/surfaceflinger/BufferStateLayer.h
+++ b/services/surfaceflinger/BufferStateLayer.h
@@ -57,7 +57,8 @@
     bool setTransform(uint32_t transform) override;
     bool setTransformToDisplayInverse(bool transformToDisplayInverse) override;
     bool setCrop(const Rect& crop) override;
-    bool setBuffer(const BufferData& bufferData, nsecs_t postTime, nsecs_t desiredPresentTime,
+    bool setBuffer(std::shared_ptr<renderengine::ExternalTexture>& /* buffer */,
+                   const BufferData& bufferData, nsecs_t postTime, nsecs_t desiredPresentTime,
                    bool isAutoTimestamp, std::optional<nsecs_t> dequeueTime,
                    const FrameTimelineInfo& info) override;
     bool setDataspace(ui::Dataspace dataspace) override;
@@ -136,9 +137,6 @@
 
     bool bufferNeedsFiltering() const override;
 
-    std::shared_ptr<renderengine::ExternalTexture> getBufferFromBufferData(
-            const BufferData& bufferData);
-
     ReleaseCallbackId mPreviousReleaseCallbackId = ReleaseCallbackId::INVALID_ID;
     uint64_t mPreviousReleasedFrameNumber = 0;