Oilpan: improve ScrollableArea handling.

Source/web/tests/PinchViewportTest.cpp

 // Copyright 2014 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.
 
 #include "config.h"
 
 #include "core/frame/PinchViewport.h"
 
 #include "core/dom/Document.h"
 #include "core/frame/FrameHost.h"
@@ skipping 190 matching lines @@
 class ParameterizedPinchViewportTest
     : public PinchViewportTest
     , public testing::WithParamInterface<SettingOverrideFunction> {
 public:
     void overrideSettings(WebSettings *settings) override
     {
         GetParam()(settings);
     }
 };
 
-#if OS(MACOSX) && ENABLE(OILPAN)
-// FIXME(504655): RootLayerScrolls configuration crashes on Mac Oilpan bots.
-INSTANTIATE_TEST_CASE_P(All, ParameterizedPinchViewportTest, ::testing::Values(
-    DefaultSettingOverride));
-#else
 static void RootLayerScrollsSettingOverride(WebSettings *settings)
 {
     settings->setRootLayerScrolls(true);
 }
 INSTANTIATE_TEST_CASE_P(All, ParameterizedPinchViewportTest, ::testing::Values(
     DefaultSettingOverride,
     RootLayerScrollsSettingOverride));
-#endif
 
 // Test that resizing the PinchViewport works as expected and that resizing the
 // WebView resizes the PinchViewport.
 TEST_P(ParameterizedPinchViewportTest, TestResize)
 {
     initializeWithDesktopSettings();
     webViewImpl()->resize(IntSize(320, 240));
 
     navigateTo("about:blank");
     forceFullCompositingUpdate();
@@ skipping 1518 matching lines @@
     webViewImpl()->handleInputEvent(pinchUpdate);
 
     PinchViewport& pinchViewport = webViewImpl()->page()->frameHost().pinchViewport();
     FrameView& frameView = *webViewImpl()->mainFrameImpl()->frameView();
 
     EXPECT_FLOAT_POINT_EQ(FloatPoint(50, 50), pinchViewport.location());
     EXPECT_FLOAT_POINT_EQ(FloatPoint(0, 0), frameView.scrollPositionDouble());
 }
 
 } // namespace