command_buffer: Implement CHROMIUM_framebuffer_mixed_samples extension

gpu/command_buffer/client/gles2_implementation_unittest_autogen.h

 // Copyright 2014 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.
 
 // This file is auto-generated from
 // gpu/command_buffer/build_gles2_cmd_buffer.py
 // It's formatted by clang-format using chromium coding style:
 //    clang-format -i -style=chromium filename
 // DO NOT EDIT!
 
@@ skipping 3208 matching lines @@
 TEST_F(GLES2ImplementationTest, StencilThenCoverStrokePathCHROMIUM) {
   struct Cmds {
     cmds::StencilThenCoverStrokePathCHROMIUM cmd;
   };
   Cmds expected;
   expected.cmd.Init(1, 2, 3, GL_CONVEX_HULL_CHROMIUM);
 
   gl_->StencilThenCoverStrokePathCHROMIUM(1, 2, 3, GL_CONVEX_HULL_CHROMIUM);
   EXPECT_EQ(0, memcmp(&expected, commands_, sizeof(expected)));
 }
+
+TEST_F(GLES2ImplementationTest, CoverageModulationCHROMIUM) {
+  struct Cmds {
+    cmds::CoverageModulationCHROMIUM cmd;
+  };
+  Cmds expected;
+  expected.cmd.Init(GL_RGB);
+
+  gl_->CoverageModulationCHROMIUM(GL_RGB);
+  EXPECT_EQ(0, memcmp(&expected, commands_, sizeof(expected)));
+}
 #endif  // GPU_COMMAND_BUFFER_CLIENT_GLES2_IMPLEMENTATION_UNITTEST_AUTOGEN_H_