Implement native GMB backbuffers in the GLES2 Command Decoder.

gpu/command_buffer/tests/gl_native_gmb_backbuffer_unittest.cc

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <GLES2/gl2.h>
+#include <GLES2/gl2ext.h>
+#include <GLES2/gl2extchromium.h>
+
+#include "gpu/command_buffer/client/gles2_lib.h"
+#include "gpu/command_buffer/service/image_factory.h"
+#include "gpu/command_buffer/tests/gl_manager.h"
+#include "gpu/command_buffer/tests/texture_image_factory.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "ui/gl/gl_context.h"
+#include "ui/gl/gl_image.h"
+
+namespace gpu {
+
+class GLNativeGMBTest : public testing::Test {
+ protected:
+  void SetUp() override {}
+
+  void TearDown() override {}
+
+  TextureImageFactory image_factory_;
+};
+
+TEST_F(GLNativeGMBTest, TestNativeGMBBackbufferWithDifferentConfigurations) {
+  for (int has_alpha = 0; has_alpha <= 1; ++has_alpha) {
+    for (int msaa = 0; msaa <= 1; ++msaa) {
+      GLManager::Options options;
+      options.image_factory = &image_factory_;
+      options.multisampled = msaa == 1;
+      options.backbuffer_alpha = has_alpha == 1;
+
+      GLManager gl;
+      gl.Initialize(options);
+      gl.MakeCurrent();
+
+      glResizeCHROMIUM(10, 10, 1, true);
+      glClearColor(0.0f, 0.25f, 0.5f, 0.7f);
+      glClear(GL_COLOR_BUFFER_BIT);
+
+      uint8_t pixel[4];
+      memset(pixel, 0, 4);
+      glReadPixels(0, 0, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, &pixel);
+      EXPECT_NEAR(0u, pixel[0], 2);
+      EXPECT_NEAR(64u, pixel[1], 2);
+      EXPECT_NEAR(127u, pixel[2], 2);
+      uint8_t alpha = has_alpha ? 178 : 255;
+      EXPECT_NEAR(alpha, pixel[3], 2);
+
+      ::gles2::GetGLContext()->SwapBuffers();
+      glClearColor(0.1f, 0.2f, 0.3f, 0.4f);
+      glClear(GL_COLOR_BUFFER_BIT);
+      memset(pixel, 0, 4);
+      glReadPixels(0, 0, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, &pixel);
+      EXPECT_NEAR(25u, pixel[0], 2);
+      EXPECT_NEAR(51u, pixel[1], 2);
+      EXPECT_NEAR(76u, pixel[2], 2);
+      uint8_t alpha2 = has_alpha ? 102 : 255;
+      EXPECT_NEAR(alpha2, pixel[3], 2);
+
+      gl.Destroy();
+    }
+  }
+}
+
+}  // namespace gpu