use SkData oriented picture serialize api

third_party/WebKit/Source/platform/graphics/paint/DrawingDisplayItem.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/DrawingDisplayItem.h"
 
 #include "platform/graphics/GraphicsContext.h"
 #include "public/platform/WebDisplayItemList.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkData.h"
 #include "third_party/skia/include/core/SkPictureAnalyzer.h"
-#include "third_party/skia/include/core/SkStream.h"
 
 namespace blink {
 
 void DrawingDisplayItem::replay(GraphicsContext& context) const
 {
     if (m_picture)
         context.drawPicture(m_picture.get());
 }
 
 void DrawingDisplayItem::appendToWebDisplayItemList(const IntRect& visualRect, WebDisplayItemList* list) const
@@ skipping 22 matching lines @@
             m_picture->cullRect().width(), m_picture->cullRect().height()));
     }
 }
 #endif
 
 static bool picturesEqual(const SkPicture* picture1, const SkPicture* picture2)
 {
     if (picture1->approximateOpCount() != picture2->approximateOpCount())
         return false;
 
-    SkDynamicMemoryWStream picture1Serialized;
-    picture1->serialize(&picture1Serialized);
-    SkDynamicMemoryWStream picture2Serialized;
-    picture2->serialize(&picture2Serialized);
-    if (picture1Serialized.bytesWritten() != picture2Serialized.bytesWritten())
-        return false;
-
-    sk_sp<SkData> data1(picture1Serialized.copyToData());
-    sk_sp<SkData> data2(picture2Serialized.copyToData());
+    sk_sp<SkData> data1 = picture1->serialize();
+    sk_sp<SkData> data2 = picture2->serialize();
     return data1->equals(data2.get());
 }
 
 static SkBitmap pictureToBitmap(const SkPicture* picture)
 {
     SkBitmap bitmap;
     SkRect rect = picture->cullRect();
     bitmap.allocPixels(SkImageInfo::MakeN32Premul(rect.width(), rect.height()));
     SkCanvas canvas(bitmap);
     canvas.clear(SK_ColorTRANSPARENT);
@@ skipping 44 matching lines @@
 
     if (picturesEqual(picture, otherPicture))
         return true;
 
     // Sometimes the client may produce different pictures for the same visual result
     // which should be treated as equal.
     return bitmapsEqual(picture, otherPicture);
 }
 
 } // namespace blink