[scheduler] Fix --disable-background-timer-throttling flag.

third_party/WebKit/Source/web/tests/scheduler/FrameThrottlingTest.cpp

 // Copyright 2015 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 "bindings/core/v8/ScriptController.h"
 #include "bindings/core/v8/ScriptSourceCode.h"
 #include "core/dom/Document.h"
 #include "core/dom/Element.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
@@ skipping 47 matching lines @@
   for (const auto& child : layer->Children())
     PaintRecursively(child, display_items);
 }
 
 }  // namespace
 
 class FrameThrottlingTest : public SimTest,
                             public ::testing::WithParamInterface<bool>,
                             private ScopedRootLayerScrollingForTest {
  protected:
-  FrameThrottlingTest() : ScopedRootLayerScrollingForTest(GetParam()) {
+  FrameThrottlingTest() : ScopedRootLayerScrollingForTest(GetParam()) {}
+
+  void SetUp() override {
+    SimTest::SetUp();
     WebView().Resize(WebSize(640, 480));
   }
 
   SimDisplayItemList CompositeFrame() {
     SimDisplayItemList display_items = Compositor().BeginFrame();
     // Ensure intersection observer notifications get delivered.
     testing::RunPendingTasks();
     return display_items;
   }
 
@@ skipping 1054 matching lines @@
   // the child. This behavior matches Safari.
   frame_element->setAttribute(styleAttr, "display: none");
   CompositeFrame();
   EXPECT_FALSE(
       frame_element->contentDocument()->View()->CanThrottleRendering());
   EXPECT_TRUE(
       child_frame_element->contentDocument()->View()->CanThrottleRendering());
 }
 
 }  // namespace blink