[net/http auth] Make HttpAuthHandler challenge handling asynchronous.

net/http/http_auth_handler_digest.h

Index: net/http/http_auth_handler_digest.h
diff --git a/net/http/http_auth_handler_digest.h b/net/http/http_auth_handler_digest.h
index 4c5052fb3be784e9e3329e6bb4888c7ae8fa8590..5a3d4165d7e933e498fe09f1b997589bb68bfdf7 100644
--- a/net/http/http_auth_handler_digest.h
+++ b/net/http/http_auth_handler_digest.h
@@ -70,7 +70,6 @@ class NET_EXPORT_PRIVATE HttpAuthHandlerDigest : public HttpAuthHandler {
         const std::string& scheme) override;
     scoped_ptr<HttpAuthHandler> CreateAndInitPreemptiveAuthHandler(
         HttpAuthCache::Entry* cache_entry,
-        const HttpAuthChallengeTokenizer& tokenizer,
         HttpAuth::Target target,
         const BoundNetLog& net_log) override;
 
@@ -78,13 +77,19 @@ class NET_EXPORT_PRIVATE HttpAuthHandlerDigest : public HttpAuthHandler {
     scoped_ptr<const NonceGenerator> nonce_generator_;
   };
 
+  // HttpAuthHandler
   HttpAuth::AuthorizationResult HandleAnotherChallenge(
       const HttpAuthChallengeTokenizer& challenge) override;
   ~HttpAuthHandlerDigest() override;
 
  protected:
-  int Init(const HttpAuthChallengeTokenizer& challenge) override;
-
+  // HttpAuthHandler
+  int InitializeFromChallengeInternal(
+      const HttpAuthChallengeTokenizer& challenge,
+      const HttpResponseInfo& response_with_challenge,
+      const CompletionCallback& callback) override;
+  int InitializeFromCacheEntryInternal(
+      HttpAuthCache::Entry* cache_entry) override;
   int GenerateAuthTokenImpl(const AuthCredentials* credentials,
                             const HttpRequestInfo& request,
                             const CompletionCallback& callback,