Add comments to SkRecordDraw to help people follow.

src/core/SkRecordDraw.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkRecordDraw.h"
 #include "SkPatchUtils.h"
 
@@ skipping 15 matching lines @@
         }
 
         SkTDArray<unsigned> ops;
         bbh->search(query, &ops);
 
         SkRecords::Draw draw(canvas);
         for (int i = 0; i < ops.count(); i++) {
             if (callback && callback->abortDrawing()) {
                 return;
             }
+            // This visit call uses the SkRecords::Draw::operator() to call
+            // methods on the |canvas|, wrapped by methods defined with the
+            // DRAW() macro.
             record.visit<void>(ops[i], draw);
         }
     } else {
         // Draw all ops.
         SkRecords::Draw draw(canvas);
         for (unsigned i = 0; i < record.count(); i++) {
             if (callback && callback->abortDrawing()) {
                 return;
             }
+            // This visit call uses the SkRecords::Draw::operator() to call
+            // methods on the |canvas|, wrapped by methods defined with the
+            // DRAW() macro.
             record.visit<void>(i, draw);
         }
     }
 }
 
 void SkRecordPartialDraw(const SkRecord& record,
                          SkCanvas* canvas,
                          const SkRect& clearRect,
                          unsigned start, unsigned stop,
                          const SkMatrix& initialCTM) {
@@ skipping 495 matching lines @@
     // Used to track the bounds of Save/Restore blocks and the control ops inside them.
     SkTDArray<SaveBounds> fSaveStack;
     SkTDArray<unsigned>   fControlIndices;
 };
 
 }  // namespace SkRecords
 
 void SkRecordFillBounds(const SkRect& cullRect, const SkRecord& record, SkBBoxHierarchy* bbh) {
     SkRecords::FillBounds(cullRect, record, bbh);
 }