Revert "MainFrame scrollbars should work with RFV instead of FV"

chrome/renderer/autofill/page_click_tracker_browsertest.cc

Index: chrome/renderer/autofill/page_click_tracker_browsertest.cc
diff --git a/chrome/renderer/autofill/page_click_tracker_browsertest.cc b/chrome/renderer/autofill/page_click_tracker_browsertest.cc
index a49ea6da4a3fae89cbadf7253479ae8551987cb1..9e1da05e5a99ecab9be010021a3a226e848d49e4 100644
--- a/chrome/renderer/autofill/page_click_tracker_browsertest.cc
+++ b/chrome/renderer/autofill/page_click_tracker_browsertest.cc
@@ -13,13 +13,9 @@
 #include "third_party/WebKit/public/platform/WebSize.h"
 #include "third_party/WebKit/public/web/WebDocument.h"
 #include "third_party/WebKit/public/web/WebInputElement.h"
-#include "third_party/WebKit/public/web/WebRuntimeFeatures.h"
 #include "third_party/WebKit/public/web/WebSettings.h"
 #include "third_party/WebKit/public/web/WebView.h"
 #include "ui/events/keycodes/keyboard_codes.h"
-#include "ui/native_theme/native_theme_switches.h"
-
-using blink::WebRuntimeFeatures;
 
 namespace autofill {
 
@@ -52,9 +48,6 @@ class PageClickTrackerTest : public ChromeRenderViewTest {
   void SetUp() override {
     ChromeRenderViewTest::SetUp();
 
-    WebRuntimeFeatures::enableOverlayScrollbars(
-        ui::IsOverlayScrollbarEnabled());
-
     // RenderView creates PageClickTracker but it doesn't keep it around.
     // Rather than make it do so for the test, we create a new object.
     page_click_tracker_.reset(new PageClickTracker(view_->GetMainRenderFrame(),