Remove the MSAA WebSetting, which is not read or used.

content/public/common/web_preferences.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.
 
 #ifndef CONTENT_PUBLIC_COMMON_WEB_PREFERENCES_H_
 #define CONTENT_PUBLIC_COMMON_WEB_PREFERENCES_H_
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 94 matching lines @@
   bool tabs_to_links;
   bool caret_browsing_enabled;
   bool hyperlink_auditing_enabled;
   bool allow_universal_access_from_file_urls;
   bool allow_file_access_from_file_urls;
   bool experimental_webgl_enabled;
   bool pepper_3d_enabled;
   bool flash_3d_enabled;
   bool flash_stage3d_enabled;
   bool flash_stage3d_baseline_enabled;
-  bool gl_multisampling_enabled;
   bool privileged_webgl_extensions_enabled;
   bool webgl_errors_to_console_enabled;
   bool mock_scrollbars_enabled;
   bool unified_textchecker_enabled;
   bool accelerated_2d_canvas_enabled;
   int minimum_accelerated_2d_canvas_size;
   bool disable_2d_canvas_copy_on_write;
   bool antialiased_2d_canvas_disabled;
   bool antialiased_clips_2d_canvas_enabled;
   int accelerated_2d_canvas_msaa_sample_count;
@@ skipping 106 matching lines @@
   // chrome, except for the cases where it would require lots of extra work for
   // the embedder to use the same default value.
   WebPreferences();
   WebPreferences(const WebPreferences& other);
   ~WebPreferences();
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_COMMON_WEB_PREFERENCES_H_