Add SetProminent() to MdTextButton to create blue buttons.

chrome/browser/ui/libgtk2ui/gtk2_ui.h

 // Copyright (c) 2013 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 CHROME_BROWSER_UI_LIBGTK2UI_GTK2_UI_H_
 #define CHROME_BROWSER_UI_LIBGTK2UI_GTK2_UI_H_
 
 #include <map>
 #include <memory>
 #include <vector>
@@ skipping 133 matching lines @@
   // background color.
   void GetNormalButtonTintHSL(color_utils::HSL* tint) const;
 
   // Returns a tint that's the color of the current normal text in an entry.
   void GetNormalEntryForegroundHSL(color_utils::HSL* tint) const;
 
   // Returns a tint that's the color of the current highlighted text in an
   // entry.
   void GetSelectedEntryForegroundHSL(color_utils::HSL* tint) const;
 
-  // Gets a color for the background of the call to action button.
-  SkColor CallToActionBgColor(int gtk_state) const;
+  // Gets a color for the background of the prominent button.
+  SkColor GetProminentButtonBgColor(int gtk_state) const;
 
   // Updates |default_font_*|.
   void UpdateDefaultFont();
 
   // Colors calculated by LoadGtkValues() that are given to the
   // caller while |use_gtk_| is true.
   ColorMap colors_;
 
   // Colors used to tint certain icons.
   color_utils::HSL button_tint_;
@@ skipping 51 matching lines @@
 }  // namespace libgtk2ui
 
 // Access point to the GTK2 desktop system. This should be the only symbol that
 // is exported in the library; everything else should be used through the
 // interface, because eventually this .so will be loaded through dlopen at
 // runtime so our main binary can conditionally load GTK2 or GTK3 or EFL or
 // QT or whatever.
 LIBGTK2UI_EXPORT views::LinuxUI* BuildGtk2UI();
 
 #endif  // CHROME_BROWSER_UI_LIBGTK2UI_GTK2_UI_H_