Detect built-in varyings' invariant setting conflicts.

gpu/command_buffer/service/shader_translator_unittest.cc

 // Copyright (c) 2012 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 "gpu/command_buffer/service/shader_translator.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace gpu {
@@ skipping 51 matching lines @@
                                             &info_log,
                                             &translated_source,
                                             &attrib_map,
                                             &uniform_map,
                                             &varying_map,
                                             &name_map));
   // Info log must be NULL.
   EXPECT_TRUE(info_log.empty());
   // Translated shader must be valid and non-empty.
   ASSERT_FALSE(translated_source.empty());
-  // There should be no attributes, uniforms, varyings.
+  // There should be no attributes, uniforms, and only one built-in
+  // varying: gl_Position.
   EXPECT_TRUE(attrib_map.empty());
   EXPECT_TRUE(uniform_map.empty());
-  EXPECT_TRUE(varying_map.empty());
+  EXPECT_EQ(1u, varying_map.size());
   // There should be no name mapping.
   EXPECT_TRUE(name_map.empty());
 }
 
 TEST_F(ShaderTranslatorTest, InvalidVertexShader) {
   const char* bad_shader = "foo-bar";
   const char* good_shader =
       "void main() {\n"
       "  gl_Position = vec4(1.0);\n"
       "}";
@@ skipping 247 matching lines @@
 
   EXPECT_EQ(options_1, options_2);
   EXPECT_NE(options_1, options_3);
   EXPECT_NE(options_1, options_4);
   EXPECT_NE(options_3, options_4);
 }
 
 }  // namespace gles2
 }  // namespace gpu