Add GL_CHROMIUM_screen_space_antialiasing to support alternative AA

gpu/command_buffer/common/gles2_cmd_format_test_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 5146 matching lines @@
 
 TEST_F(GLES2FormatTest, BlendBarrierKHR) {
   cmds::BlendBarrierKHR& cmd = *GetBufferAs<cmds::BlendBarrierKHR>();
   void* next_cmd = cmd.Set(&cmd);
   EXPECT_EQ(static_cast<uint32_t>(cmds::BlendBarrierKHR::kCmdId),
             cmd.header.command);
   EXPECT_EQ(sizeof(cmd), cmd.header.size * 4u);
   CheckBytesWrittenMatchesExpectedSize(next_cmd, sizeof(cmd));
 }
 
+TEST_F(GLES2FormatTest, ApplyScreenSpaceAntialiasing) {
+  cmds::ApplyScreenSpaceAntialiasing& cmd =
+      *GetBufferAs<cmds::ApplyScreenSpaceAntialiasing>();
+  void* next_cmd = cmd.Set(&cmd);
+  EXPECT_EQ(static_cast<uint32_t>(cmds::ApplyScreenSpaceAntialiasing::kCmdId),
+            cmd.header.command);
+  EXPECT_EQ(sizeof(cmd), cmd.header.size * 4u);
+  CheckBytesWrittenMatchesExpectedSize(next_cmd, sizeof(cmd));
+}
+
 #endif  // GPU_COMMAND_BUFFER_COMMON_GLES2_CMD_FORMAT_TEST_AUTOGEN_H_