Make RenderingTest to use ScopedOverlayScrollbarsForTest

RenderingTest::SetUp has been using RuntimeEnabledFeatures::SetOverlayScrollbarsEnabled
for testing. This CL remove the use, instead make it to use ScopedOverlayScrollbarsForTest.

Bug: 769541
Change-Id: I7fa923adc379ad219065bdc57c54878dea637acd
Reviewed-on: https://chromium-review.googlesource.com/762968
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Reviewed-by: Xianzhu Wang <wangxianzhu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#515961}

third_party/WebKit/Source/core/frame/FrameTestHelpers.h

@@ -40,6 +40,7 @@
 #include "platform/WebTaskRunner.h"
 #include "platform/runtime_enabled_features.h"
 #include "platform/scroll/ScrollbarTheme.h"
+#include "platform/testing/UseMockScrollbarSettings.h"
 #include "platform/testing/WebLayerTreeViewImplForTesting.h"
 #include "public/platform/Platform.h"
 #include "public/platform/WebMouseEvent.h"
@@ -158,42 +159,6 @@ WebRemoteFrameImpl* CreateRemoteChild(WebRemoteFrame& parent,
                                       scoped_refptr<SecurityOrigin> = nullptr,
                                       TestWebRemoteFrameClient* = nullptr);
 
-// Forces to use mocked overlay scrollbars instead of the default native theme
-// scrollbars to avoid crash in Chromium code when it tries to load UI
-// resources that are not available when running blink unit tests, and to
-// ensure consistent layout regardless of differences between scrollbar themes.
-// WebViewHelper includes this, so this is only needed if a test doesn't use
-// WebViewHelper or the test needs a bigger scope of mock scrollbar settings
-// than the scope of WebViewHelper.
-class UseMockScrollbarSettings {
- public:
-  UseMockScrollbarSettings()
-      : original_mock_scrollbar_enabled_(Settings::MockScrollbarsEnabled()),
-        original_overlay_scrollbars_enabled_(
-            RuntimeEnabledFeatures::OverlayScrollbarsEnabled()) {
-    Settings::SetMockScrollbarsEnabled(true);
-    RuntimeEnabledFeatures::SetOverlayScrollbarsEnabled(true);
-  }
-
-  UseMockScrollbarSettings(bool use_mock, bool use_overlay)
-      : original_mock_scrollbar_enabled_(Settings::MockScrollbarsEnabled()),
-        original_overlay_scrollbars_enabled_(
-            RuntimeEnabledFeatures::OverlayScrollbarsEnabled()) {
-    Settings::SetMockScrollbarsEnabled(use_mock);
-    RuntimeEnabledFeatures::SetOverlayScrollbarsEnabled(use_overlay);
-  }
-
-  ~UseMockScrollbarSettings() {
-    Settings::SetMockScrollbarsEnabled(original_mock_scrollbar_enabled_);
-    RuntimeEnabledFeatures::SetOverlayScrollbarsEnabled(
-        original_overlay_scrollbars_enabled_);
-  }
-
- private:
-  bool original_mock_scrollbar_enabled_;
-  bool original_overlay_scrollbars_enabled_;
-};
-
 class TestWebWidgetClient : public WebWidgetClient {
  public:
   ~TestWebWidgetClient() override {}

third_party/WebKit/Source/core/layout/LayoutTestHelper.cpp

@@ -39,7 +39,7 @@ ChromeClient& RenderingTest::GetChromeClient() const {
 }
 
 RenderingTest::RenderingTest(LocalFrameClient* local_frame_client)
-    : local_frame_client_(local_frame_client) {}
+    : UseMockScrollbarSettings(), local_frame_client_(local_frame_client) {}
 
 void RenderingTest::SetUp() {
   Page::PageClients page_clients;
@@ -47,7 +47,6 @@ void RenderingTest::SetUp() {
   page_clients.chrome_client = &GetChromeClient();
   SetupPageWithClients(&page_clients, local_frame_client_, SettingOverrider());
   Settings::SetMockScrollbarsEnabled(true);
-  RuntimeEnabledFeatures::SetOverlayScrollbarsEnabled(true);
   EXPECT_TRUE(
       GetDocument().GetPage()->GetScrollbarTheme().UsesOverlayScrollbars());
 

third_party/WebKit/Source/core/layout/LayoutTestHelper.h

@@ -17,6 +17,7 @@
 #include "core/layout/api/LayoutViewItem.h"
 #include "core/loader/EmptyClients.h"
 #include "core/testing/PageTestBase.h"
+#include "platform/testing/UseMockScrollbarSettings.h"
 #include "platform/wtf/Allocator.h"
 
 namespace blink {
@@ -66,7 +67,7 @@ class LocalFrameClientWithParent final : public EmptyLocalFrameClient {
   Member<LocalFrame> parent_;
 };
 
-class RenderingTest : public PageTestBase {
+class RenderingTest : public PageTestBase, public UseMockScrollbarSettings {
   USING_FAST_MALLOC(RenderingTest);
 
  public:
@@ -75,7 +76,7 @@ class RenderingTest : public PageTestBase {
   }
   virtual ChromeClient& GetChromeClient() const;
 
-  RenderingTest(LocalFrameClient* = nullptr);
+  explicit RenderingTest(LocalFrameClient* = nullptr);
 
  protected:
   void SetUp() override;

third_party/WebKit/Source/core/layout/ScrollbarsTest.cpp

@@ -1322,7 +1322,7 @@ class ScrollbarAppearanceTest
   ScrollbarAppearanceTest() : mock_scrollbars_(false, GetParam()) {}
 
  private:
-  FrameTestHelpers::UseMockScrollbarSettings mock_scrollbars_;
+  UseMockScrollbarSettings mock_scrollbars_;
 };
 
 class StubWebThemeEngine : public WebThemeEngine {

third_party/WebKit/Source/platform/BUILD.gn

@@ -1670,6 +1670,7 @@ jumbo_static_library("test_support") {
     "testing/URLTestHelpers.h",
     "testing/UnitTestHelpers.cpp",
     "testing/UnitTestHelpers.h",
+    "testing/UseMockScrollbarSettings.h",
     "testing/WebLayerTreeViewImplForTesting.cpp",
     "testing/WebLayerTreeViewImplForTesting.h",
     "testing/weburl_loader_mock.cc",

third_party/WebKit/Source/platform/testing/UseMockScrollbarSettings.h

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef UseMockScrollbarSettings_h
+#define UseMockScrollbarSettings_h
+
+#include "platform/scroll/ScrollbarTheme.h"
+#include "platform/testing/RuntimeEnabledFeaturesTestHelpers.h"
+
+namespace blink {
+
+// Forces to use mocked overlay scrollbars instead of the default native theme
+// scrollbars to avoid crash in Chromium code when it tries to load UI
+// resources that are not available when running blink unit tests, and to
+// ensure consistent layout regardless of differences between scrollbar themes.
+// WebViewHelper includes this, so this is only needed if a test doesn't use
+// WebViewHelper or the test needs a bigger scope of mock scrollbar settings
+// than the scope of WebViewHelper.
+class UseMockScrollbarSettings : private ScopedOverlayScrollbarsForTest {
+ public:
+  UseMockScrollbarSettings()
+      : ScopedOverlayScrollbarsForTest(true),
+        original_mock_scrollbar_enabled_(
+            ScrollbarTheme::MockScrollbarsEnabled()),
+        original_overlay_scrollbars_enabled_(
+            RuntimeEnabledFeatures::OverlayScrollbarsEnabled()) {
+    ScrollbarTheme::SetMockScrollbarsEnabled(true);
+  }
+
+  UseMockScrollbarSettings(bool use_mock, bool use_overlay)
+      : ScopedOverlayScrollbarsForTest(use_overlay),
+        original_mock_scrollbar_enabled_(
+            ScrollbarTheme::MockScrollbarsEnabled()),
+        original_overlay_scrollbars_enabled_(
+            RuntimeEnabledFeatures::OverlayScrollbarsEnabled()) {
+    ScrollbarTheme::SetMockScrollbarsEnabled(use_mock);
+  }
+
+  ~UseMockScrollbarSettings() {
+    ScrollbarTheme::SetMockScrollbarsEnabled(original_mock_scrollbar_enabled_);
+  }
+
+ private:
+  bool original_mock_scrollbar_enabled_;
+  bool original_overlay_scrollbars_enabled_;
+};
+
+}  // namespace blink
+
+#endif  // UseMockScrollbarSettings_h