Validate hash_sha256 checksum on .crx update.

chrome/browser/extensions/crx_installer.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_EXTENSIONS_CRX_INSTALLER_H_
 #define CHROME_BROWSER_EXTENSIONS_CRX_INSTALLER_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 82 matching lines @@
   // Same as the previous method, except use the |approval| to bypass the
   // prompt. Note that the caller retains ownership of |approval|.
   static scoped_refptr<CrxInstaller> Create(
       ExtensionService* service,
       scoped_ptr<ExtensionInstallPrompt> client,
       const WebstoreInstaller::Approval* approval);
 
   // Install the crx in |source_file|.
   void InstallCrx(const base::FilePath& source_file);
 
+  // Install the crx in |source_file| after checking hash sum.
+  void CheckAndInstallCrx(const base::FilePath& source_file,
+                          const std::string& package_hash);
+
   // Convert the specified user script into an extension and install it.
   void InstallUserScript(const base::FilePath& source_file,
                          const GURL& download_url);
 
   // Convert the specified web app into an extension and install it.
   void InstallWebApp(const WebApplicationInfo& web_app);
 
   // Overridden from ExtensionInstallPrompt::Delegate:
   void InstallUIProceed() override;
   void InstallUIAbort(bool user_initiated) override;
@@ skipping 307 matching lines @@
 
   // Performs requirements, policy and blacklist checks on the extension.
   ExtensionInstallChecker install_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(CrxInstaller);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_CRX_INSTALLER_H_