Add unittests for gl_surface_egl to cover the changes in crrev.com/2698573002.

ui/gl/gl_surface_egl_unittest.cc

+// Copyright 2017 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 "ui/gl/gl_surface_egl.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "ui/gl/gl_implementation.h"
+#include "ui/gl/init/gl_factory.h"
+#include "ui/gl/test/gl_surface_test_support.h"
+
+namespace gl {
+
+class GLSurfaceEGLTest : public testing::Test {};
+
+TEST(GLSurfaceEGLTest, SurfaceFormatTest) {
+  GLSurfaceTestSupport::InitializeOneOffImplementation(
+      GLImplementation::kGLImplementationEGLGLES2, true);
+
+  GLSurfaceFormat surface_format = GLSurfaceFormat();
+  surface_format.SetDepthBits(24);
+  surface_format.SetStencilBits(8);
+  surface_format.SetSamples(0);
+  scoped_refptr<GLSurface> surface =
+      init::CreateOffscreenGLSurfaceWithFormat(gfx::Size(1, 1), surface_format);
+  EGLConfig config = surface->GetConfig();
+  EXPECT_TRUE(config);
+
+  EGLint attrib;
+  eglGetConfigAttrib(surface->GetDisplay(), config, EGL_DEPTH_SIZE, &attrib);
+  EXPECT_LE(24, attrib);
+
+  eglGetConfigAttrib(surface->GetDisplay(), config, EGL_STENCIL_SIZE, &attrib);
+  EXPECT_LE(8, attrib);
+
+  eglGetConfigAttrib(surface->GetDisplay(), config, EGL_SAMPLES, &attrib);
+  EXPECT_EQ(0, attrib);
+}
+
+}  // namespace gl