Update SkImage_NewFromTexture test

tests/ImageTest.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include <functional>
 #include <initializer_list>
 #include <vector>
@@ skipping 727 matching lines @@
 #endif
 
 #if SK_SUPPORT_GPU
 struct TextureReleaseChecker {
     TextureReleaseChecker() : fReleaseCount(0) {}
     int fReleaseCount;
     static void Release(void* self) {
         static_cast<TextureReleaseChecker*>(self)->fReleaseCount++;
     }
 };
-static void check_image_color(skiatest::Reporter* reporter, SkImage* image, SkPMColor expected) {
-    const SkImageInfo info = SkImageInfo::MakeN32Premul(1, 1);
-    SkPMColor pixel;
-    REPORTER_ASSERT(reporter, image->readPixels(info, &pixel, sizeof(pixel), 0, 0));
-    REPORTER_ASSERT(reporter, pixel == expected);
-}
-DEF_GPUTEST_FOR_GL_RENDERING_CONTEXTS(SkImage_NewFromTexture, reporter, ctxInfo) {
+DEF_GPUTEST_FOR_GL_RENDERING_CONTEXTS(SkImage_NewFromTextureRelease, reporter, ctxInfo) {
     GrTextureProvider* provider = ctxInfo.grContext()->textureProvider();
     const int w = 10;
     const int h = 10;
-    SkPMColor storage[w * h];
-    const SkPMColor expected0 = SkPreMultiplyColor(SK_ColorRED);
-    sk_memset32(storage, expected0, w * h);
     GrSurfaceDesc desc;
-    desc.fFlags = kRenderTarget_GrSurfaceFlag;  // needs to be a rendertarget for readpixels();
+    desc.fFlags = kRenderTarget_GrSurfaceFlag;
     desc.fOrigin = kDefault_GrSurfaceOrigin;
     desc.fWidth = w;
     desc.fHeight = h;
     desc.fConfig = kSkia8888_GrPixelConfig;
     desc.fSampleCnt = 0;
-    SkAutoTUnref<GrTexture> tex(provider->createTexture(desc, SkBudgeted::kNo, storage, w * 4));
+    SkAutoTUnref<GrTexture> tex(provider->createTexture(desc, SkBudgeted::kNo));
     if (!tex) {
         REPORTER_ASSERT(reporter, false);
         return;
     }
 
     GrBackendTextureDesc backendDesc;
     backendDesc.fConfig = kSkia8888_GrPixelConfig;
     backendDesc.fFlags = kRenderTarget_GrBackendTextureFlag;
     backendDesc.fWidth = w;
     backendDesc.fHeight = h;
     backendDesc.fSampleCnt = 0;
     backendDesc.fTextureHandle = tex->getTextureHandle();

[bsalomon, 2016/07/21 20:57:44]

Can we get rid of 'tex' and use

backendDesc.fTextureHandle =
ctxInfo.grContext()->getGpu()->createTestingOnlyBackendTexture(
        pixels.get(), w, h, kRGBA_8888_GrPixelConfig, true);

?

At the end of the test we'd also need
ctxInfo.grContext()->getGpu()->deleteTestingOnlyBackendTexture(backendDesc.fTextureHandle);

     TextureReleaseChecker releaseChecker;
     sk_sp<SkImage> refImg(
         SkImage::MakeFromTexture(ctxInfo.grContext(), backendDesc, kPremul_SkAlphaType,
                                  TextureReleaseChecker::Release, &releaseChecker));
 
-    check_image_color(reporter, refImg.get(), expected0);
-
-    // Now lets jam new colors into our "external" texture, and see if the images notice
-    const SkPMColor expected1 = SkPreMultiplyColor(SK_ColorBLUE);
-    sk_memset32(storage, expected1, w * h);
-    tex->writePixels(0, 0, w, h, kSkia8888_GrPixelConfig, storage, GrContext::kFlushWrites_PixelOp);
-
-    // The cpy'd one should still see the old color
-#if 0
-    // There is no guarantee that refImg sees the new color. We are free to have made a copy. Our
-    // write pixels call violated the contract with refImg and refImg is now undefined.
-    check_image_color(reporter, refImg, expected1);
-#endif
-
     // Now exercise the release proc
     REPORTER_ASSERT(reporter, 0 == releaseChecker.fReleaseCount);
     refImg.reset(nullptr); // force a release of the image
     REPORTER_ASSERT(reporter, 1 == releaseChecker.fReleaseCount);
 }
 
 static void check_images_same(skiatest::Reporter* reporter, const SkImage* a, const SkImage* b) {
     if (a->width() != b->width() || a->height() != b->height()) {
         ERRORF(reporter, "Images must have the same size");
         return;
@@ skipping 149 matching lines @@
                         otherContextInfo.grContext(), buffer, budgeted));
                     REPORTER_ASSERT(reporter, !newImage2);
                     testContext->makeCurrent();
                 }
             }
             sk_free(buffer);
         }
     }
 }
 #endif