Content Verification: Don't access UI-thread objects on the IO thread

extensions/browser/content_verifier_delegate.h

 // Copyright 2014 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_BROWSER_CONTENT_VERIFIER_DELEGATE_H_
 #define EXTENSIONS_BROWSER_CONTENT_VERIFIER_DELEGATE_H_
 
 #include <set>
 
 #include "url/gurl.h"
@@ skipping 37 matching lines @@
     // If hashes are present, enforce them. If they are missing, try to fetch
     // them.
     ENFORCE,
 
     // Treat the absence of hashes the same as a verification failure.
     ENFORCE_STRICT
   };
 
   virtual ~ContentVerifierDelegate() {}
 
-  // This should return true if the given extension should have its content
-  // verified.
+  // This should return what verification mode is appropriate for the given
+  // extension, if any.
   virtual Mode ShouldBeVerified(const Extension& extension) = 0;
 
   // Should return the public key to use for validating signatures via the two
   // out parameters. NOTE: the pointer returned *must* remain valid for the
   // lifetime of this object.
   virtual const ContentVerifierKey& PublicKey() = 0;
 
   // This should return a URL that can be used to fetch the
   // verified_contents.json containing signatures for the given extension
   // id/version pair.
   virtual GURL GetSignatureFetchUrl(const std::string& extension_id,
                                     const base::Version& version) = 0;
 
   // This should return the set of file paths for images used within the
   // browser process. (These may get transcoded during the install process).
   virtual std::set<base::FilePath> GetBrowserImagePaths(
       const extensions::Extension* extension) = 0;
 
   // Called when the content verifier detects that a read of a file inside
   // an extension did not match its expected hash.
   virtual void VerifyFailed(const std::string& extension_id) = 0;
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_CONTENT_VERIFIER_DELEGATE_H_