Use refs for non-null GraphicsContext, Scrollbar, etc. in scrollbar related code

third_party/WebKit/Source/platform/scroll/ScrollableAreaTest.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 "config.h"
 #include "platform/scroll/ScrollableArea.h"
 
 #include "platform/scroll/ScrollbarTheme.h"
 #include "platform/scroll/ScrollbarThemeMock.h"
 #include "platform/testing/TestingPlatformSupport.h"
@@ skipping 108 matching lines @@
 
 private:
     FakePlatform m_fakePlatform;
     Platform* m_oldPlatform; // Not owned.
 };
 
 TEST_F(ScrollableAreaTest, ScrollAnimatorCurrentPositionShouldBeSync)
 {
     OwnPtrWillBeRawPtr<MockScrollableArea> scrollableArea = MockScrollableArea::create(IntPoint(0, 100));
     scrollableArea->setScrollPosition(IntPoint(0, 10000), CompositorScroll);
-    EXPECT_EQ(100.0, scrollableArea->scrollAnimator()->currentPosition().y());
+    EXPECT_EQ(100.0, scrollableArea->scrollAnimator().currentPosition().y());
 }
 
 TEST_F(ScrollableAreaTest, ScrollbarTrackAndThumbRepaint)
 {
     ScrollbarTheme::setMockScrollbarsEnabled(true);
     ScrollbarThemeMock::setShouldRepaintAllPartsOnInvalidation(true);
 
     OwnPtrWillBeRawPtr<MockScrollableArea> scrollableArea = MockScrollableArea::create(IntPoint(0, 100));
     RefPtrWillBeRawPtr<Scrollbar> scrollbar = Scrollbar::create(scrollableArea.get(), HorizontalScrollbar, RegularScrollbar);
 
@@ skipping 15 matching lines @@
     scrollbar->setTrackNeedsRepaint(false);
     scrollbar->setThumbNeedsRepaint(false);
     EXPECT_FALSE(scrollbar->trackNeedsRepaint());
     EXPECT_FALSE(scrollbar->thumbNeedsRepaint());
     scrollbar->setNeedsPaintInvalidation();
     EXPECT_FALSE(scrollbar->trackNeedsRepaint());
     EXPECT_FALSE(scrollbar->thumbNeedsRepaint());
 }
 
 } // namespace blink