Gtk3 ui: Add libgtk3ui as a separate build component

chrome/browser/ui/libgtkui/app_indicator_icon.cc

Index: chrome/browser/ui/libgtkui/app_indicator_icon.cc
diff --git a/chrome/browser/ui/libgtk2ui/app_indicator_icon.cc b/chrome/browser/ui/libgtkui/app_indicator_icon.cc
similarity index 98%
rename from chrome/browser/ui/libgtk2ui/app_indicator_icon.cc
rename to chrome/browser/ui/libgtkui/app_indicator_icon.cc
index f0e9cec873a4a337bd1fe45dbcf3a996667d3f8d..3aafd0ab9629c0b5c527ade4afcc15f86ae17052 100644
--- a/chrome/browser/ui/libgtk2ui/app_indicator_icon.cc
+++ b/chrome/browser/ui/libgtkui/app_indicator_icon.cc
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "chrome/browser/ui/libgtk2ui/app_indicator_icon.h"
+#include "chrome/browser/ui/libgtkui/app_indicator_icon.h"
 
 #include <dlfcn.h>
 #include <gtk/gtk.h>
@@ -15,7 +15,7 @@
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/sequenced_worker_pool.h"
-#include "chrome/browser/ui/libgtk2ui/app_indicator_icon_menu.h"
+#include "chrome/browser/ui/libgtkui/app_indicator_icon_menu.h"
 #include "content/public/browser/browser_thread.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/skia/include/core/SkCanvas.h"
@@ -171,7 +171,7 @@ void DeleteTempDirectory(const base::FilePath& dir_path) {
 
 }  // namespace
 
-namespace libgtk2ui {
+namespace libgtkui {
 
 AppIndicatorIcon::AppIndicatorIcon(std::string id,
                                    const gfx::ImageSkia& image,
@@ -394,4 +394,4 @@ void AppIndicatorIcon::OnClickActionReplacementMenuItemActivated() {
     delegate()->OnClick();
 }
 
-}  // namespace libgtk2ui
+}  // namespace libgtkui