Revert of Change extension icon load errors to warnings

extensions/common/file_util.h

 // Copyright 2013 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 EXTENSIONS_COMMON_FILE_UTIL_H_
 #define EXTENSIONS_COMMON_FILE_UTIL_H_
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 54 matching lines @@
 scoped_ptr<base::DictionaryValue> LoadManifest(
     const base::FilePath& extension_root,
     std::string* error);
 
 // Convenience overload for specifying a manifest filename.
 scoped_ptr<base::DictionaryValue> LoadManifest(
     const base::FilePath& extension_root,
     const base::FilePath::CharType* manifest_filename,
     std::string* error);
 
-// Returns true if the given file path exists and is not zero-length.
-bool ValidateFilePath(const base::FilePath& path);
-
 // Returns true if the given extension object is valid and consistent.
 // May also append a series of warning messages to |warnings|, but they
 // should not prevent the extension from running.
 //
 // Otherwise, returns false, and a description of the error is
 // returned in |error|.
 bool ValidateExtension(const Extension* extension,
                        std::string* error,
                        std::vector<InstallWarning>* warnings);
 
@@ skipping 63 matching lines @@
     const ExtensionSet& extension_set);
 
 // Helper functions for getting paths for files used in content verification.
 base::FilePath GetVerifiedContentsPath(const base::FilePath& extension_path);
 base::FilePath GetComputedHashesPath(const base::FilePath& extension_path);
 
 }  // namespace file_util
 }  // namespace extensions
 
 #endif  // EXTENSIONS_COMMON_FILE_UTIL_H_