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

third_party/WebKit/Source/core/frame/RootFrameViewport.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 "core/frame/RootFrameViewport.h"
 
 #include "core/frame/FrameView.h"
 #include "core/layout/ScrollAlignment.h"
 #include "platform/geometry/DoubleRect.h"
 #include "platform/geometry/FloatRect.h"
 #include "platform/geometry/LayoutRect.h"
 
 namespace blink {
 
 RootFrameViewport::RootFrameViewport(ScrollableArea& visualViewport, ScrollableArea& layoutViewport, bool invertScrollOrder)
     : m_visualViewport(visualViewport)
     , m_layoutViewport(layoutViewport)
     , m_invertScrollOrder(invertScrollOrder)
 {
 }
 
 void RootFrameViewport::updateScrollAnimator()
 {
-    scrollAnimator()->setCurrentPosition(toFloatPoint(scrollOffsetFromScrollAnimators()));
+    scrollAnimator().setCurrentPosition(toFloatPoint(scrollOffsetFromScrollAnimators()));
 }
 
 DoublePoint RootFrameViewport::scrollOffsetFromScrollAnimators() const
 {
-    return visualViewport().scrollAnimator()->currentPosition() + layoutViewport().scrollAnimator()->currentPosition();
+    return visualViewport().scrollAnimator().currentPosition() + layoutViewport().scrollAnimator().currentPosition();
 }
 
 DoubleRect RootFrameViewport::visibleContentRectDouble(IncludeScrollbarsInRect scrollbarInclusion) const
 {
     return DoubleRect(scrollPositionDouble(), visualViewport().visibleContentRectDouble(scrollbarInclusion).size());
 }
 
 IntRect RootFrameViewport::visibleContentRect(IncludeScrollbarsInRect scrollbarInclusion) const
 {
     return enclosingIntRect(visibleContentRectDouble(scrollbarInclusion));
@@ skipping 53 matching lines @@
 }
 
 LayoutRect RootFrameViewport::scrollIntoView(const LayoutRect& rectInContent, const ScrollAlignment& alignX, const ScrollAlignment& alignY, ScrollType scrollType)
 {
     // We want to move the rect into the viewport that excludes the scrollbars so we intersect
     // the visual viewport with the scrollbar-excluded frameView content rect. However, we don't
     // use visibleContentRect directly since it floors the scroll position. Instead, we use
     // ScrollAnimatorBase::currentPosition and construct a LayoutRect from that.
 
     LayoutRect frameRectInContent = LayoutRect(
-        layoutViewport().scrollAnimator()->currentPosition(),
+        layoutViewport().scrollAnimator().currentPosition(),
         layoutViewport().visibleContentRect().size());
     LayoutRect visualRectInContent = LayoutRect(
         scrollOffsetFromScrollAnimators(),
         visualViewport().visibleContentRect().size());
 
     // Intersect layout and visual rects to exclude the scrollbar from the view rect.
     LayoutRect viewRectInContent = intersection(visualRectInContent, frameRectInContent);
     LayoutRect targetViewport =
         ScrollAlignment::getRectToExpose(viewRectInContent, rectInContent, alignX, alignY);
     DoublePoint targetOffset(targetViewport.x(), targetViewport.y());
@@ skipping 22 matching lines @@
     DoublePoint oldPosition = scrollOffsetFromScrollAnimators();
 
     DoubleSize delta = offset - oldPosition;
 
     if (delta.isZero())
         return;
 
     ScrollableArea& primary = !m_invertScrollOrder ? layoutViewport() : visualViewport();
     ScrollableArea& secondary = !m_invertScrollOrder ? visualViewport() : layoutViewport();
 
-    DoublePoint targetPosition = primary.clampScrollPosition(primary.scrollAnimator()->currentPosition() + delta);
+    DoublePoint targetPosition = primary.clampScrollPosition(primary.scrollAnimator().currentPosition() + delta);
     primary.setScrollPosition(targetPosition, scrollType, behavior);
 
     // Scroll the secondary viewport if all of the scroll was not applied to the
     // primary viewport.
-    DoublePoint updatedPosition = secondary.scrollAnimator()->currentPosition() + FloatPoint(targetPosition);
+    DoublePoint updatedPosition = secondary.scrollAnimator().currentPosition() + FloatPoint(targetPosition);
     DoubleSize applied = updatedPosition - oldPosition;
     delta -= applied;
 
     if (delta.isZero())
         return;
 
-    targetPosition = secondary.clampScrollPosition(secondary.scrollAnimator()->currentPosition() + delta);
+    targetPosition = secondary.clampScrollPosition(secondary.scrollAnimator().currentPosition() + delta);
     secondary.setScrollPosition(targetPosition, scrollType, behavior);
 }
 
 IntPoint RootFrameViewport::scrollPosition() const
 {
     return flooredIntPoint(scrollPositionDouble());
 }
 
 DoublePoint RootFrameViewport::scrollPositionDouble() const
 {
@@ skipping 113 matching lines @@
 }
 
 DEFINE_TRACE(RootFrameViewport)
 {
     visitor->trace(m_visualViewport);
     visitor->trace(m_layoutViewport);
     ScrollableArea::trace(visitor);
 }
 
 } // namespace blink