Make a test not depend on system settings.

content/browser/site_per_process_browsertest.cc

Index: content/browser/site_per_process_browsertest.cc
diff --git a/content/browser/site_per_process_browsertest.cc b/content/browser/site_per_process_browsertest.cc
index d427d924b893206ee97e80ef97773e0433dd1c31..aaf095051fb383df9dcf037cbbf0e6d7ff111f84 100644
--- a/content/browser/site_per_process_browsertest.cc
+++ b/content/browser/site_per_process_browsertest.cc
@@ -51,6 +51,10 @@
 #include "third_party/WebKit/public/web/WebSandboxFlags.h"
 #include "ui/gfx/switches.h"
 
+#if defined(OS_MACOSX)
+#include "content/browser/theme_helper_mac.h"
+#endif
+
 namespace content {
 
 namespace {
@@ -2009,6 +2013,10 @@ IN_PROC_BROWSER_TEST_F(SitePerProcessBrowserTest,
 #endif
 IN_PROC_BROWSER_TEST_F(SitePerProcessBrowserTest,
                        MAYBE_FrameOwnerPropertiesPropagationScrolling) {
+#if defined(OS_MACOSX)
+  ScopedPreferredScrollerStyleOveride
+      scroller_style(blink::ScrollerStyleLegacy);
+#endif
   GURL main_url(embedded_test_server()->GetURL(
       "a.com", "/frame_owner_properties_scrolling.html"));
   NavigateToURL(shell(), main_url);