Eliminate all UI thread decoding of extension images....

chrome/common/extensions/extension.h

 // Copyright (c) 2010 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 CHROME_COMMON_EXTENSIONS_EXTENSION_H_
 #define CHROME_COMMON_EXTENSIONS_EXTENSION_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 167 matching lines @@
   // Expects base64 encoded |input| and formats into |output| including
   // the appropriate header & footer.
   static bool FormatPEMForFileOutput(const std::string input,
       std::string* output, bool is_public);
 
   // Determine whether |new_extension| has increased privileges compared to
   // |old_extension|.
   static bool IsPrivilegeIncrease(Extension* old_extension,
                                   Extension* new_extension);
 
+  // *** HITS THE FILESYSTEM. Do not call on UI thread! ***
   // Given an extension and icon size, read it if present and decode it into
   // result.
+  // NOTE: If you need the icon on the UI thread, please use the
+  // ImageLoadingTracker, which uses the File thread to decode.
   static void DecodeIcon(Extension* extension,
                          Icons icon_size,
                          scoped_ptr<SkBitmap>* result);
 
+  // *** HITS THE FILESYSTEM. Do not call on UI thread! ***
   // Given an icon_path and icon size, read it if present and decode it into
   // result.
+  // NOTE: If you need the icon on the UI thread, please use the
+  // ImageLoadingTracker, which uses the File thread to decode.
   static void DecodeIconFromPath(const FilePath& icon_path,
                                  Icons icon_size,
                                  scoped_ptr<SkBitmap>* result);
 
   // Initialize the extension from a parsed manifest.
   // Usually, the id of an extension is generated by the "key" property of
   // its manifest, but if |require_key| is |false|, a temporary ID will be
   // generated based on the path.
   bool InitFromValue(const DictionaryValue& value, bool require_key,
                      std::string* error);
@@ skipping 300 matching lines @@
   scoped_ptr<DictionaryValue> extension_manifest;
   std::string extension_id;
   FilePath extension_path;
   Extension::Location extension_location;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ExtensionInfo);
 };
 
 #endif  // CHROME_COMMON_EXTENSIONS_EXTENSION_H_