Adding a Views scrollbar implementation.

views/controls/scrollbar/native_scroll_bar_gtk.cc

Index: views/controls/scrollbar/native_scroll_bar_gtk.cc
diff --git a/views/controls/scrollbar/native_scroll_bar_gtk.cc b/views/controls/scrollbar/native_scroll_bar_gtk.cc
index dc1a9b68d219856e0f2395641c75192ebbac425a..645ec2d0544722bdfa8714bced9649a8de250f72 100644
--- a/views/controls/scrollbar/native_scroll_bar_gtk.cc
+++ b/views/controls/scrollbar/native_scroll_bar_gtk.cc
@@ -8,7 +8,9 @@
 
 #include "ui/base/keycodes/keyboard_codes_posix.h"
 #include "views/controls/scrollbar/native_scroll_bar.h"
+#include "views/controls/scrollbar/native_scroll_bar_views.h"
 #include "views/controls/scrollbar/scroll_bar.h"
+#include "views/widget/widget.h"
 
 namespace views {
 
@@ -199,6 +201,8 @@ void NativeScrollBarGtk::MoveToBottom() {
 // static
 NativeScrollBarWrapper* NativeScrollBarWrapper::CreateWrapper(
     NativeScrollBar* scroll_bar) {
+  if (Widget::IsPureViews())
+    return new NativeScrollBarViews(scroll_bar);
   return new NativeScrollBarGtk(scroll_bar);
 }