Move preferred scrollbar style preference change listening from renderer to browser, 3 of 3.

Source/web/mac/WebScrollbarTheme.mm

Index: Source/web/mac/WebScrollbarTheme.mm
diff --git a/Source/web/mac/WebScrollbarTheme.cpp b/Source/web/mac/WebScrollbarTheme.mm
similarity index 77%
rename from Source/web/mac/WebScrollbarTheme.cpp
rename to Source/web/mac/WebScrollbarTheme.mm
index 0f9791c6bc1ce83e70120e45aec827728a600248..7adb6cec8c79dce3e97efd7d8fce32a4e17fdf3e 100644
--- a/Source/web/mac/WebScrollbarTheme.cpp
+++ b/Source/web/mac/WebScrollbarTheme.mm
@@ -31,35 +31,28 @@
 #include "config.h"
 #include "WebScrollbarTheme.h"
 
+#import <AppKit/AppKit.h>
+
 #include "platform/scroll/ScrollbarThemeMacCommon.h"
+#include "platform/mac/NSScrollerImpDetails.h"
 
 using namespace WebCore;
 
 namespace blink {
 
-#if defined(MAC_OS_X_VERSION_10_7) && MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_7
-// TODO(rsesek): Reenable this after making sure it actually builds.
-//COMPILE_ASSERT(ScrollerStyleLegacy == NSScrollerStyleLegacy, ScrollerStyle_Legacy_must_be_equal);
-//COMPILE_ASSERT(ScrollerStyleOverlay == NSScrollerStyleOverlay, ScrollerStyle_Overlay_must_be_equal);
-#endif
+COMPILE_ASSERT(ScrollerStyleLegacy == NSScrollerStyleLegacy, ScrollerStyle_Legacy_must_be_equal);
+COMPILE_ASSERT(ScrollerStyleOverlay == NSScrollerStyleOverlay, ScrollerStyle_Overlay_must_be_equal);
 
 void WebScrollbarTheme::updateScrollbars(
     float initialButtonDelay, float autoscrollButtonDelay,
-    bool jumpOnTrackClick, bool redraw)
+    bool jumpOnTrackClick, ScrollerStyle preferredScrollerStyle, bool redraw)
 {
     ScrollbarTheme* theme = ScrollbarTheme::theme();
     if (theme->isMockTheme())
         return;
 
     static_cast<ScrollbarThemeMacCommon*>(ScrollbarTheme::theme())->preferencesChanged(
-        initialButtonDelay, autoscrollButtonDelay, jumpOnTrackClick, redraw);
-}
-
-void WebScrollbarTheme::updateScrollbars(
-    float initialButtonDelay, float autoscrollButtonDelay,
-    bool jumpOnTrackClick, ScrollerStyle preferredScrollerStyle, bool redraw)
-{
-    updateScrollbars(initialButtonDelay, autoscrollButtonDelay, jumpOnTrackClick, redraw);
+        initialButtonDelay, autoscrollButtonDelay, jumpOnTrackClick, preferredScrollerStyle, redraw);
 }
 
 } // namespace blink