Revert "Revert "Add ExternalTexture class into RenderEngine inte..."

Revert submission 14199598-revert-14086921-renderengine-external-tex-QJNBWQMQEU

Reason for revert: Prepare for relanding
Reverted Changes:
I01e65a7f4:Revert "Update WaylandRenderSurface to accomodate ...
I7d58118c1:Revert "Update Readback VTS to align with RenderEn...
I1501890f4:Revert "Add ExternalTexture class into RenderEngin...

Added the following fixes:
1. CachedSet renders to intermediate texture variable rather than
mTexture directly, since mTexture is not guaranteed to be nonnull.
2. Add null check when setting new buffer in BLAST.

Bug: 185524947
Bug: 180767535
Test: builds, boots
Test: librenderengine_test
Change-Id: I52ea82e24336b496d996bbe3e445db0affe1abb8
diff --git a/libs/renderengine/skia/SkiaRenderEngine.h b/libs/renderengine/skia/SkiaRenderEngine.h
index 51ef088..308c5ff 100644
--- a/libs/renderengine/skia/SkiaRenderEngine.h
+++ b/libs/renderengine/skia/SkiaRenderEngine.h
@@ -42,15 +42,12 @@
     virtual void primeCache() override{};
     virtual void genTextures(size_t /*count*/, uint32_t* /*names*/) override{};
     virtual void deleteTextures(size_t /*count*/, uint32_t const* /*names*/) override{};
-    virtual void cacheExternalTextureBuffer(const sp<GraphicBuffer>& /*buffer*/){};
-    virtual void unbindExternalTextureBuffer(uint64_t /*bufferId*/){};
-
     virtual bool isProtected() const override { return false; } // mInProtectedContext; }
     virtual bool supportsProtectedContent() const override { return false; };
     virtual bool useProtectedContext(bool /*useProtectedContext*/) override { return false; };
     virtual status_t drawLayers(const DisplaySettings& /*display*/,
                                 const std::vector<const LayerSettings*>& /*layers*/,
-                                const sp<GraphicBuffer>& /*buffer*/,
+                                const std::shared_ptr<ExternalTexture>& /*buffer*/,
                                 const bool /*useFramebufferCache*/,
                                 base::unique_fd&& /*bufferFence*/,
                                 base::unique_fd* /*drawFence*/) override {
@@ -60,6 +57,11 @@
     virtual int getContextPriority() override { return 0; }
     virtual void assertShadersCompiled(int numShaders) {}
     virtual int reportShadersCompiled() { return 0; }
+
+protected:
+    virtual void mapExternalTextureBuffer(const sp<GraphicBuffer>& /*buffer*/,
+                                          bool /*isRenderable*/) override;
+    virtual void unmapExternalTextureBuffer(const sp<GraphicBuffer>& /*buffer*/) override;
 };
 
 } // namespace skia