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/libs/renderengine/tests/RenderEngineThreadedTest.cpp b/libs/renderengine/tests/RenderEngineThreadedTest.cpp
index db7e12b..9685189 100644
--- a/libs/renderengine/tests/RenderEngineThreadedTest.cpp
+++ b/libs/renderengine/tests/RenderEngineThreadedTest.cpp
@@ -17,6 +17,7 @@
 #include <cutils/properties.h>
 #include <gmock/gmock.h>
 #include <gtest/gtest.h>
+#include <renderengine/impl/ExternalTexture.h>
 #include <renderengine/mock/RenderEngine.h>
 #include "../threaded/RenderEngineThreaded.h"
 
@@ -174,9 +175,10 @@
     renderengine::DisplaySettings settings;
     std::vector<renderengine::LayerSettings> layers;
     std::shared_ptr<renderengine::ExternalTexture> buffer = std::make_shared<
-            renderengine::ExternalTexture>(new GraphicBuffer(), *mRenderEngine,
-                                           renderengine::ExternalTexture::Usage::READABLE |
-                                                   renderengine::ExternalTexture::Usage::WRITEABLE);
+            renderengine::impl::
+                    ExternalTexture>(new GraphicBuffer(), *mRenderEngine,
+                                     renderengine::impl::ExternalTexture::Usage::READABLE |
+                                             renderengine::impl::ExternalTexture::Usage::WRITEABLE);
 
     base::unique_fd bufferFence;