Validate hash_sha256 checksum on .crx update.

chrome/browser/extensions/extension_service.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_EXTENSION_SERVICE_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_SERVICE_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 69 matching lines @@
   // the install can be started. Sets |out_crx_installer| to the installer if
   // one was started.
   // TODO(aa): This method can be removed. ExtensionUpdater could use
   // CrxInstaller directly instead.
   virtual bool UpdateExtension(
       const std::string& id,
       const base::FilePath& path,
       bool file_ownership_passed,
       extensions::CrxInstaller** out_crx_installer) = 0;
 
+  // Same as above, but checks .crx file hash sum as well.
+  virtual bool CheckAndUpdateExtension(
+      const std::string& id,
+      const base::FilePath& path,
+      const std::string& hash,
+      bool file_ownership_passed,
+      extensions::CrxInstaller** out_crx_installer) = 0;
+
   // DEPRECATED. Use ExtensionRegistry instead.
   //
   // Looks up an extension by its ID.
   //
   // If |include_disabled| is false then this will only include enabled
   // extensions. Use instead:
   //
   //   ExtensionRegistry::enabled_extensions().GetByID(id).
   //
   // If |include_disabled| is true then this will also include disabled and
@@ skipping 103 matching lines @@
   extensions::PendingExtensionManager* pending_extension_manager() override;
   const extensions::Extension* GetExtensionById(
       const std::string& id,
       bool include_disabled) const override;
   const extensions::Extension* GetInstalledExtension(
       const std::string& id) const override;
   bool UpdateExtension(const std::string& id,
                        const base::FilePath& extension_path,
                        bool file_ownership_passed,
                        extensions::CrxInstaller** out_crx_installer) override;
+  bool CheckAndUpdateExtension(
+      const std::string& id,
+      const base::FilePath& extension_path,
+      const std::string& package_hash,
+      bool file_ownership_passed,
+      extensions::CrxInstaller** out_crx_installer) override;
   bool IsExtensionEnabled(const std::string& extension_id) const override;
   void UnloadExtension(
       const std::string& extension_id,
       extensions::UnloadedExtensionInfo::Reason reason) override;
   void RemoveComponentExtension(const std::string& extension_id) override;
   void AddExtension(const extensions::Extension* extension) override;
   void AddComponentExtension(const extensions::Extension* extension) override;
   const extensions::Extension* GetPendingExtensionUpdate(
       const std::string& extension_id) const override;
   void FinishDelayedInstallation(const std::string& extension_id) override;
@@ skipping 528 matching lines @@
                            GreylistUnknownDontChange);
   FRIEND_TEST_ALL_PREFIXES(ExtensionServiceTest,
                            ManagementPolicyProhibitsEnableOnInstalled);
   FRIEND_TEST_ALL_PREFIXES(ExtensionServiceTest,
                            BlockAndUnblockBlacklistedExtension);
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionService);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_SERVICE_H_