Use a new Supplement constructor for Supplement<Document> (Part 1)

third_party/WebKit/Source/core/paint/PaintTiming.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 "core/paint/PaintTiming.h"
 
 #include "core/dom/Document.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
 #include "core/loader/DocumentLoader.h"
@@ skipping 54 matching lines @@
   TRACE_EVENT_MARK_WITH_TIMESTAMP1(
       "blink.user_timing,rail", "firstImagePaint",
       TraceEvent::toTraceTimestamp(m_firstImagePaint), "frame", frame());
   notifyPaintTimingChanged();
 }
 
 void PaintTiming::markFirstMeaningfulPaintCandidate() {
   if (m_firstMeaningfulPaintCandidate)
     return;
   m_firstMeaningfulPaintCandidate = monotonicallyIncreasingTime();
-  if (m_document->frame() && m_document->frame()->view() &&
-      !m_document->frame()->view()->parent()) {
-    m_document->frame()->frameScheduler()->onFirstMeaningfulPaint();
+  if (frame() && frame()->view() && !frame()->view()->parent()) {
+    frame()->frameScheduler()->onFirstMeaningfulPaint();
   }
 }
 
 void PaintTiming::setFirstMeaningfulPaint(double stamp) {
   DCHECK_EQ(m_firstMeaningfulPaint, 0.0);
   m_firstMeaningfulPaint = stamp;
   TRACE_EVENT_MARK_WITH_TIMESTAMP1(
       "blink.user_timing", "firstMeaningfulPaint",
       TraceEvent::toTraceTimestamp(m_firstMeaningfulPaint), "frame", frame());
   notifyPaintTimingChanged();
 }
 
 void PaintTiming::notifyPaint(bool isFirstPaint,
                               bool textPainted,
                               bool imagePainted) {
   if (isFirstPaint)
     markFirstPaint();
   if (textPainted)
     markFirstTextPaint();
   if (imagePainted)
     markFirstImagePaint();
   m_fmpDetector->notifyPaint();
 }
 
 DEFINE_TRACE(PaintTiming) {
-  visitor->trace(m_document);
   visitor->trace(m_fmpDetector);
   Supplement<Document>::trace(visitor);
 }
 
 PaintTiming::PaintTiming(Document& document)
-    : m_document(document),
+    : Supplement<Document>(document),
       m_fmpDetector(new FirstMeaningfulPaintDetector(this)) {}
 
 LocalFrame* PaintTiming::frame() const {
-  return m_document ? m_document->frame() : nullptr;
+  return host()->frame();
 }
 
 void PaintTiming::notifyPaintTimingChanged() {
-  if (m_document && m_document->loader())
-    m_document->loader()->didChangePerformanceTiming();
+  if (host()->loader())
+    host()->loader()->didChangePerformanceTiming();
 }
 
 void PaintTiming::setFirstPaint(double stamp) {
   if (m_firstPaint != 0.0)
     return;
   m_firstPaint = stamp;
   TRACE_EVENT_INSTANT1("blink.user_timing,rail", "firstPaint",
                        TRACE_EVENT_SCOPE_PROCESS, "frame", frame());
 }
 
 void PaintTiming::setFirstContentfulPaint(double stamp) {
   if (m_firstContentfulPaint != 0.0)
     return;
   setFirstPaint(stamp);
   m_firstContentfulPaint = stamp;
   TRACE_EVENT_INSTANT1("blink.user_timing,rail", "firstContentfulPaint",
                        TRACE_EVENT_SCOPE_PROCESS, "frame", frame());
 }
 
 }  // namespace blink