Extract InstallVerifier from ExtensionSystem.

chrome/browser/extensions/install_verifier.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 CHROME_BROWSER_EXTENSIONS_INSTALL_VERIFIER_H_
 #define CHROME_BROWSER_EXTENSIONS_INSTALL_VERIFIER_H_
 
 #include <queue>
 #include <set>
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/memory/linked_ptr.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
+#include "components/keyed_service/core/keyed_service.h"
 #include "extensions/browser/management_policy.h"
 #include "extensions/common/extension.h"
 
 namespace content {
 class BrowserContext;
 }
 
 namespace net {
 class URLRequestContextGetter;
 }
 
 namespace extensions {
 
 class ExtensionPrefs;
 class InstallSigner;
 struct InstallSignature;
 
 // This class implements verification that a set of extensions are either from
 // the webstore or are whitelisted by enterprise policy.  The webstore
 // verification process works by sending a request to a backend server to get a
 // signature proving that a set of extensions are verified. This signature is
 // written into the extension preferences and is checked for validity when
 // being read back again.
 //
 // This class should be kept notified of runtime changes to the set of
 // extensions installed from the webstore.
-class InstallVerifier : public ManagementPolicy::Provider {
+class InstallVerifier : public KeyedService,
+                        public ManagementPolicy::Provider {
  public:
   InstallVerifier(ExtensionPrefs* prefs, content::BrowserContext* context);
   ~InstallVerifier() override;
 
+  // Convenience method to return the InstallVerifier for a given |context|.
+  static InstallVerifier* Get(content::BrowserContext* context);
+
   // Returns whether install verification should be enforced.
   static bool ShouldEnforce();
 
   // Returns whether |extension| is of a type that needs verification.
   static bool NeedsVerification(const Extension& extension);
 
   // Determines if an extension claims to be from the webstore.
   static bool IsFromStore(const Extension& extension);
 
   // Initializes this object for use, including reading preferences and
@@ skipping 114 matching lines @@
   ExtensionIdSet provisional_;
 
   base::WeakPtrFactory<InstallVerifier> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(InstallVerifier);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_INSTALL_VERIFIER_H_