Gtk3 ui: Add libgtk3ui as a separate build component

chrome/browser/ui/libgtkui/app_indicator_icon.h

Index: chrome/browser/ui/libgtkui/app_indicator_icon.h
diff --git a/chrome/browser/ui/libgtk2ui/app_indicator_icon.h b/chrome/browser/ui/libgtkui/app_indicator_icon.h
similarity index 91%
rename from chrome/browser/ui/libgtk2ui/app_indicator_icon.h
rename to chrome/browser/ui/libgtkui/app_indicator_icon.h
index 2bd2f1eb0b1666c6683f453e4a46017f46403a2a..38e936fe0d3a09c22e2b9bf80162806ec6338463 100644
--- a/chrome/browser/ui/libgtk2ui/app_indicator_icon.h
+++ b/chrome/browser/ui/libgtkui/app_indicator_icon.h
@@ -2,8 +2,8 @@
 // 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_APP_INDICATOR_ICON_H_
-#define CHROME_BROWSER_UI_LIBGTK2UI_APP_INDICATOR_ICON_H_
+#ifndef CHROME_BROWSER_UI_LIBGTKUI_APP_INDICATOR_ICON_H_
+#define CHROME_BROWSER_UI_LIBGTKUI_APP_INDICATOR_ICON_H_
 
 #include <memory>
 
@@ -11,7 +11,7 @@
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/nix/xdg_util.h"
-#include "chrome/browser/ui/libgtk2ui/gtk2_signal.h"
+#include "chrome/browser/ui/libgtkui/gtk2_signal.h"
 #include "ui/views/linux_ui/status_icon_linux.h"
 
 typedef struct _AppIndicator AppIndicator;
@@ -27,7 +27,7 @@ namespace ui {
 class MenuModel;
 }
 
-namespace libgtk2ui {
+namespace libgtkui {
 class AppIndicatorIconMenu;
 
 // Status icon implementation which uses libappindicator.
@@ -105,6 +105,6 @@ class AppIndicatorIcon : public views::StatusIconLinux {
   DISALLOW_COPY_AND_ASSIGN(AppIndicatorIcon);
 };
 
-}  // namespace libgtk2ui
+}  // namespace libgtkui
 
-#endif  // CHROME_BROWSER_UI_LIBGTK2UI_APP_INDICATOR_ICON_H_
+#endif  // CHROME_BROWSER_UI_LIBGTKUI_APP_INDICATOR_ICON_H_