Fix a crash when saving a <canvas> or <img> image which is large.

content/common/content_constants_internal.h

 // Copyright (c) 2012 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 CONTENT_COMMON_CONTENT_CONSTANTS_INTERNAL_H_
 #define CONTENT_COMMON_CONTENT_CONSTANTS_INTERNAL_H_
 
 #include "base/basictypes.h"
 #include "content/common/content_export.h"
 
 namespace content {
 
 // How long to wait before we consider a renderer hung.
 CONTENT_EXPORT extern const int kHungRendererDelayMs;
 
 // The maximum plugin width and height.
 extern const uint16 kMaxPluginSideLength;
 // The maximum plugin size, defined as the number of pixels occupied by the
 // plugin.
 extern const uint32 kMaxPluginSize;
 
+// The maximum length of string as data url.
+extern const size_t kMaxLengthOfDataURLString;
+
 // Constants used to organize content processes in about:tracing.
 CONTENT_EXPORT extern const int kTraceEventBrowserProcessSortIndex;
 CONTENT_EXPORT extern const int kTraceEventRendererProcessSortIndex;
 CONTENT_EXPORT extern const int kTraceEventPluginProcessSortIndex;
 CONTENT_EXPORT extern const int kTraceEventPpapiProcessSortIndex;
 CONTENT_EXPORT extern const int kTraceEventPpapiBrokerProcessSortIndex;
 CONTENT_EXPORT extern const int kTraceEventGpuProcessSortIndex;
 
 // Constants used to organize content threads in about:tracing.
 CONTENT_EXPORT extern const int kTraceEventRendererMainThreadSortIndex;
 
 } // namespace content
 
 #endif  // CONTENT_COMMON_CONTENT_CONSTANTS_INTERNAL_H_