First fix to minimize copying of image data.

chrome/browser/dom_ui/fileicon_source.cc

 // Copyright (c) 2009 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 "chrome/browser/dom_ui/fileicon_source.h"
 
 #include "app/gfx/codec/png_codec.h"
 #include "base/string_util.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/common/time_format.h"
@@ skipping 21 matching lines @@
   // this only appears to matter for getting icons from .exe files.
   std::replace(escaped_path.begin(), escaped_path.end(), '/', '\\');
   FilePath escaped_filepath(UTF8ToWide(escaped_path));
 #elif defined(OS_POSIX)
   // The correct encoding on Linux may not actually be UTF8.
   FilePath escaped_filepath(escaped_path);
 #endif
   SkBitmap* icon = im->LookupIcon(escaped_filepath, IconLoader::NORMAL);
 
   if (icon) {
-    std::vector<unsigned char> png_bytes;
-    gfx::PNGCodec::EncodeBGRASkBitmap(*icon, false, &png_bytes);
+    scoped_refptr<RefCountedBytes> icon_data = new RefCountedBytes;
+    gfx::PNGCodec::EncodeBGRASkBitmap(*icon, false, &icon_data->data);
 
-    scoped_refptr<RefCountedBytes> icon_data = new RefCountedBytes(png_bytes);
     SendResponse(request_id, icon_data);
   } else {
     // Icon was not in cache, go fetch it slowly.
     IconManager::Handle h = im->LoadIcon(escaped_filepath,
         IconLoader::NORMAL,
         &cancelable_consumer_,
         NewCallback(this, &FileIconSource::OnFileIconDataAvailable));
 
     // Attach the ChromeURLDataManager request ID to the history request.
     cancelable_consumer_.SetClientData(im, h, request_id);
   }
 }
 
 void FileIconSource::OnFileIconDataAvailable(IconManager::Handle handle,
                                              SkBitmap* icon) {
   IconManager* im = g_browser_process->icon_manager();
   int request_id = cancelable_consumer_.GetClientData(im, handle);
 
   if (icon) {
-    std::vector<unsigned char> png_bytes;
-    gfx::PNGCodec::EncodeBGRASkBitmap(*icon, false, &png_bytes);
+    scoped_refptr<RefCountedBytes> icon_data = new RefCountedBytes;
+    gfx::PNGCodec::EncodeBGRASkBitmap(*icon, false, &icon_data->data);
 
-    scoped_refptr<RefCountedBytes> icon_data = new RefCountedBytes(png_bytes);
     SendResponse(request_id, icon_data);
   } else {
     // TODO(glen): send a dummy icon.
     SendResponse(request_id, NULL);
   }
 }