Cache render targets that render to wrapped textures

tests/SurfaceTest.cpp

Index: tests/SurfaceTest.cpp
diff --git a/tests/SurfaceTest.cpp b/tests/SurfaceTest.cpp
index 89c7765c5601326a1bc6b1ce84cf024d6ece1329..8cf880339dac2883f899c4c86c6f7f0ca69c8247 100644
--- a/tests/SurfaceTest.cpp
+++ b/tests/SurfaceTest.cpp
@@ -900,4 +900,43 @@ DEF_GPUTEST_FOR_RENDERING_CONTEXTS(SurfaceClear_Gpu, reporter, context) {
         context->getGpu()->deleteTestingOnlyBackendTexture(textureObject);
     }
 }
+
+DEF_GPUTEST_FOR_RENDERING_CONTEXTS(ExternalTextureSurfaceUsesRenderTargetCache_Gpu, reporter,
+                                   context) {
+
+    static const int kWidth = 10;
+    static const int kHeight = 10;
+    SkAutoTDeleteArray<uint32_t> pixels(new uint32_t[kWidth * kHeight]);
+    memset(pixels.get(), 0xAB, sizeof(uint32_t) * kWidth * kHeight);
+
+    GrBackendObject textureObject =
+            context->getGpu()->createTestingOnlyBackendTexture(pixels.get(), kWidth, kHeight,
+                                                               kRGBA_8888_GrPixelConfig);
+    GrBackendTextureDesc desc;
+    desc.fConfig = kRGBA_8888_GrPixelConfig;
+    desc.fWidth = kWidth;
+    desc.fHeight = kHeight;
+    desc.fFlags = kRenderTarget_GrBackendTextureFlag;
+    desc.fTextureHandle = textureObject;
+
+    for (auto sampleCnt : { 0, 4 }) {
+        desc.fSampleCnt = sampleCnt;
+
+        SkAutoTUnref<SkSurface> surface1(
+            SkSurface::NewFromBackendTextureAsRenderTarget(context, desc, nullptr));
+        GrBackendObject surface1_id;
+        REPORTER_ASSERT(reporter, surface1->getRenderTargetHandle(
+            &surface1_id, SkSurface::kFlushRead_BackendHandleAccess));
+        // TODO: check for clear.
+        SkAutoTUnref<SkSurface> surface2(
+            SkSurface::NewFromBackendTextureAsRenderTarget(context, desc, nullptr));
+        GrBackendObject surface2_id;
+        REPORTER_ASSERT(reporter, surface2->getRenderTargetHandle(
+            &surface2_id, SkSurface::kFlushRead_BackendHandleAccess));
+        // TODO: check for clear.
+
+        REPORTER_ASSERT(reporter, surface1_id == surface2_id);
+    }
+    context->getGpu()->deleteTestingOnlyBackendTexture(textureObject);
+}
 #endif