Allow default font size changing on Linux.

content/public/common/renderer_preferences.h

 // 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.
 //
 // A struct for managing browser's settings that apply to the renderer or its
 // webview.  These differ from WebPreferences since they apply to Chromium's
 // glue layer rather than applying to just WebKit.
 //
 // Adding new values to this class probably involves updating
 // common/view_messages.h, browser/browser.cc, etc.
@@ skipping 157 matching lines @@
   // The height of a horizontal scroll bar in dips.
   int32 horizontal_scroll_bar_height_in_dips;
 
   // The height of the arrow bitmap on a vertical scroll bar in dips.
   int32 arrow_bitmap_height_vertical_scroll_bar_in_dips;
 
   // The width of the arrow bitmap on a horizontal scroll bar in dips.
   int32 arrow_bitmap_width_horizontal_scroll_bar_in_dips;
 #endif
 
+  // The default font size used for rendering on Linux.
+  int default_font_size;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_COMMON_RENDERER_PREFERENCES_H_