Use UtilityProcessHost to patch files.

chrome/browser/component_updater/component_unpacker.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 CHROME_BROWSER_COMPONENT_UPDATER_COMPONENT_UNPACKER_H_
 #define CHROME_BROWSER_COMPONENT_UPDATER_COMPONENT_UNPACKER_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 76 matching lines @@
     kDeltaMissingExistingFile,
     kFingerprintWriteFailed,
   };
 
   // Constructs an unpacker for a specific component unpacking operation.
   // |pk_hash| is the expected/ public key SHA256 hash. |path| is the current
   // location of the CRX.
   ComponentUnpacker(const std::vector<uint8>& pk_hash,
                     const base::FilePath& path,
                     const std::string& fingerprint,
-                    ComponentPatcher* patcher,
                     ComponentInstaller* installer,
+                    bool in_process,
                     scoped_refptr<base::SequencedTaskRunner> task_runner);
 
   virtual ~ComponentUnpacker();
 
   // Begins the actual unpacking of the files. May invoke a patcher if the
   // package is a differential update. Calls |callback| with the result.
-  void Unpack(
-      const base::Callback<void(Error, int)>& callback);
+  void Unpack(const base::Callback<void(Error, int)>& callback);
 
  private:
   bool UnpackInternal();
 
   // The first step of unpacking is to verify the file. Returns false if an
   // error is encountered, the file is malformed, or the file is incorrectly
   // signed.
   bool Verify();
 
   // The second step of unpacking is to unzip. Returns false if an error
@@ skipping 20 matching lines @@
 
   // Returns a weak pointer to this object.
   base::WeakPtr<ComponentUnpacker> GetWeakPtr();
 
   std::vector<uint8> pk_hash_;
   base::FilePath path_;
   base::FilePath unpack_path_;
   base::FilePath unpack_diff_path_;
   bool is_delta_;
   std::string fingerprint_;
-  ComponentPatcher* patcher_;
+  scoped_ptr<ComponentPatcher> patcher_;
   ComponentInstaller* installer_;
   base::Callback<void(Error, int)> callback_;
+  bool in_process_;

[Sorin Jianu, 2014/02/03 20:57:57]

const?

[waffles, 2014/02/07 01:00:59]

Done.

   Error error_;
   int extended_error_;
   base::WeakPtrFactory<ComponentUnpacker> ptr_factory_;
   scoped_refptr<base::SequencedTaskRunner> task_runner_;
 
   DISALLOW_COPY_AND_ASSIGN(ComponentUnpacker);
 };
 
 }  // namespace component_updater
 
 #endif  // CHROME_BROWSER_COMPONENT_UPDATER_COMPONENT_UNPACKER_H_