Move background related shorthands into CSSPropertyParser

third_party/WebKit/Source/core/paint/PaintTiming.h

 // 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.
 
 #ifndef PaintTiming_h
 #define PaintTiming_h
 
 #include "core/dom/Document.h"
 #include "platform/Supplementable.h"
 #include "platform/heap/Handle.h"
+#include "wtf/Noncopyable.h"
 
 namespace blink {
 
 class LocalFrame;
 
+// PaintTiming is responsible for tracking paint-related timings for a given
+// document.
 class PaintTiming final : public NoBaseWillBeGarbageCollectedFinalized<PaintTiming>, public WillBeHeapSupplement<Document> {
+    WTF_MAKE_NONCOPYABLE(PaintTiming);
     WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(PaintTiming);
 public:
     virtual ~PaintTiming() { }
 
     static PaintTiming& from(Document&);
 
+    // mark*() methods record the time for the given paint event, record a trace
+    // event, and notify that paint timing has changed. These methods do nothing
+    // (early return) if a time has already been recorded for the given paint
+    // event.
     void markFirstPaint();
+
+    // markFirstTextPaint, markFirstImagePaint, and markFirstContentfulPaint
+    // will also record first paint if first paint hasn't been recorded yet.
+    void markFirstContentfulPaint();
+
+    // markFirstTextPaint and markFirstImagePaint will also record first
+    // contentful paint if first contentful paint hasn't been recorded yet.
     void markFirstTextPaint();
     void markFirstImagePaint();
-    void markFirstContentfulPaint();
 
-    // These return monotonically-increasing seconds.
+    // The getters below return monotonically-increasing seconds, or zero if the
+    // given paint event has not yet occurred. See the comments for
+    // monotonicallyIncreasingTime in wtf/CurrentTime.h for additional details.
+
+    // firstPaint returns the first time that anything was painted for the
+    // current document.
     double firstPaint() const { return m_firstPaint; }
+
+    // firstContentfulPaint returns the first time that 'contentful' content was
+    // painted. For instance, the first time that text or image content was
+    // painted.
+    double firstContentfulPaint() const { return m_firstContentfulPaint; }
+
+    // firstTextPaint returns the first time that text content was painted.
     double firstTextPaint() const { return m_firstTextPaint; }
+
+    // firstImagePaint returns the first time that image content was painted.
     double firstImagePaint() const { return m_firstImagePaint; }
-    double firstContentfulPaint() const { return m_firstContentfulPaint; }
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     explicit PaintTiming(Document&);
     LocalFrame* frame() const;
     void notifyPaintTimingChanged();
 
+    // set*() set the timing for the given paint event to the given timestamp
+    // and record a trace event if the value is currently zero, but do not
+    // notify that paint timing changed. These methods can be invoked from other
+    // mark*() or set*() methods to make sure that first paint is marked as part
+    // of marking first contentful paint, or that first contentful paint is
+    // marked as part of marking first text/image paint, for example.
+    void setFirstPaint(double stamp);
+
+    // setFirstContentfulPaint will also set first paint time if first paint
+    // time has not yet been recorded.
+    void setFirstContentfulPaint(double stamp);
+
     double m_firstPaint = 0.0;
     double m_firstTextPaint = 0.0;
     double m_firstImagePaint = 0.0;
     double m_firstContentfulPaint = 0.0;
 
     RawPtrWillBeMember<Document> m_document;
 };
 
 } // namespace blink
 
 #endif