Linux Aura: Use system title bar is now set by preference, not flag.

chrome/browser/resources/options/browser_options.html

Index: chrome/browser/resources/options/browser_options.html
diff --git a/chrome/browser/resources/options/browser_options.html b/chrome/browser/resources/options/browser_options.html
index 76b98da36c2be58c45d50892dbc5e167e6d793bb..5f4c409f98cd6f94835a0f318f533cf90030b017 100644
--- a/chrome/browser/resources/options/browser_options.html
+++ b/chrome/browser/resources/options/browser_options.html
@@ -82,7 +82,7 @@
         </span>
       </span>
     </div>
-<if expr="not pp_ifdef('toolkit_views') and is_posix and not is_macosx">
+<if expr="is_posix and not pp_ifdef('chromeos') and not is_macosx">

[msw, 2014/02/06 00:50:27]

Will this break GTK, which is shipping for M-24?

[Elliot Glaysher, 2014/02/06 00:52:30]

Theoretically, this shouldn't.

[Matt Giuca, 2014/02/11 04:57:43]

Tested on GTK; it still shows the checkbox. (Not sure what the concern was.)

[msw, 2014/02/11 19:32:59]

I wasn't sure if we want this on GTK or not. You addressed my
browser_command_controller.cc nits to exclude GTK, but then you noted that the
checkbox is still available on GTK here. I'm still a bit confused.

[Matt Giuca, 2014/02/12 01:09:18]

This is already a GTK feature. We aren't trying to remove it on GTK, just add it
on Aura. (Maybe that explains the confusion?)

     <div class="checkbox"><label>
         <input id="show-window-decorations" type="checkbox"
             pref="browser.custom_chrome_frame" metric="Options_CustomFrame"