Add debugging output for visual rects in PaintController.

third_party/WebKit/Source/platform/graphics/paint/PaintController.cpp

 // Copyright 2014 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 "platform/graphics/paint/PaintController.h"
 
 #include "platform/TraceEvent.h"
 #include "platform/graphics/GraphicsLayer.h"
 #include "platform/graphics/paint/DrawingDisplayItem.h"
 #include "third_party/skia/include/core/SkPictureAnalyzer.h"
@@ skipping 474 matching lines @@
     }
 #endif // NDEBUG
 
     NOTREACHED();
 }
 
 #endif // DCHECK_IS_ON()
 
 #ifndef NDEBUG
 
-WTF::String PaintController::displayItemListAsDebugString(const DisplayItemList& list) const
+String PaintController::displayItemListAsDebugString(const DisplayItemList& list) const
 {
     StringBuilder stringBuilder;
     size_t i = 0;
     for (auto it = list.begin(); it != list.end(); ++it, ++i) {
         const DisplayItem& displayItem = *it;
         if (i)
             stringBuilder.append(",\n");
         stringBuilder.append(String::format("{index: %d, ", (int)i));
         displayItem.dumpPropertiesAsDebugString(stringBuilder);
         if (displayItem.hasValidClient()) {
             stringBuilder.append(", cacheIsValid: ");
             stringBuilder.append(clientCacheIsValid(displayItem.client()) ? "true" : "false");
         }
+        IntRect visualRect = list.visualRect(i);

[wkorman, 2016/07/01 19:04:06]

I think that this can/will lead to a failed DCHECK assert with i >= visual rect
vector size, in this debug block:

https://cs.chromium.org/chromium/src/third_party/WebKit/Source/platform/graph...

+        stringBuilder.append(String::format(", visualRect: [%d,%d %dx%d]",
+            visualRect.x(), visualRect.y(),
+            visualRect.width(), visualRect.height()));
         stringBuilder.append('}');
     }
     return stringBuilder.toString();
 }
 
 void PaintController::showDebugData() const
 {
     WTFLogAlways("current display item list: [%s]\n", displayItemListAsDebugString(m_currentPaintArtifact.getDisplayItemList()).utf8().data());
     WTFLogAlways("new display item list: [%s]\n", displayItemListAsDebugString(m_newDisplayItemList).utf8().data());
 }
 
 #endif // ifndef NDEBUG
 
 } // namespace blink