Refactor sync passphrase setup flow and fix passphrase tests

chrome/browser/sync/engine/syncapi.h

 // Copyright (c) 2011 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.
 
 // This file defines the "sync API", an interface to the syncer
 // backend that exposes (1) the core functionality of maintaining a consistent
 // local snapshot of a hierarchical object set; (2) a means to transactionally
 // access and modify those objects; (3) a means to control client/server
 // synchronization tasks, namely: pushing local object modifications to a
 // server, pulling nonlocal object modifications from a server to this client,
@@ skipping 89 matching lines @@
 class TypedUrlSpecifics;
 }
 
 namespace sync_api {
 
 class BaseTransaction;
 class HttpPostProviderFactory;
 class SyncManager;
 class WriteTransaction;
 
+// Reasons due to which browser_sync::Cryptographer might require a passphrase.
+enum PassphraseRequiredReason {
+  REASON_PASSPHRASE_NOT_REQUIRED = 0,  // Initial value.
+  REASON_ENCRYPTION = 1,               // The cryptographer requires a
+                                       // passphrase for its first attempt at
+                                       // encryption. Happens only during
+                                       // migration or upgrade.
+  REASON_DECRYPTION = 2,               // The cryptographer requires a
+                                       // passphrase for its first attempt at
+                                       // decryption.
+  REASON_SET_PASSPHRASE_FAILED = 3,    // The cryptographer requires a new
+                                       // passphrase because its attempt at
+                                       // decryption with the cached passphrase
+                                       // was unsuccessful.
+};
+
+// Returns the string representation of a PassphraseRequiredReason value.
+std::string PassphraseRequiredReasonToString(PassphraseRequiredReason reason);
+
 // A UserShare encapsulates the syncable pieces that represent an authenticated
 // user and their data (share).
 // This encompasses all pieces required to build transaction objects on the
 // syncable share.
 struct UserShare {
   UserShare();
   ~UserShare();
 
   // The DirectoryManager itself, which is the parent of Transactions and can
   // be shared across multiple threads (unlike Directory).
@@ skipping 652 matching lines @@
     virtual void OnSyncCycleCompleted(
         const browser_sync::sessions::SyncSessionSnapshot* snapshot) = 0;
 
     // Called when user interaction may be required due to an auth problem.
     virtual void OnAuthError(const GoogleServiceAuthError& auth_error) = 0;
 
     // Called when a new auth token is provided by the sync server.
     virtual void OnUpdatedToken(const std::string& token) = 0;
 
     // Called when user interaction is required to obtain a valid passphrase.
-    // If the passphrase is required to decrypt something that has
-    // already been encrypted (and thus has to match the existing key),
-    // |for_decryption| will be true.  If the passphrase is needed for
-    // encryption, |for_decryption| will be false.
-    virtual void OnPassphraseRequired(bool for_decryption) = 0;
-
-    // Called only by SyncInternal::SetPassphrase to indiciate that an attempted
-    // passphrase failed to decrypt pending keys. This is different from
-    // OnPassphraseRequired in that it denotes we finished an attempt to set
-    // a passphrase. OnPassphraseRequired means we have data we could not
-    // decrypt yet, and can come from numerous places.
-    virtual void OnPassphraseFailed() = 0;
+    // - If the passphrase is required for encryption, |reason| will be
+    //   REASON_ENCRYPTION.
+    // - If the passphrase is required for the decryption of data that has
+    //   already been encrypted, |reason| will be REASON_DECRYPTION.
+    // - If the passphrase is required because decryption failed, and a new
+    //   passphrase is required, |reason| will be REASON_SET_PASSPHRASE_FAILED.
+    virtual void OnPassphraseRequired(PassphraseRequiredReason reason) = 0;
 
     // Called when the passphrase provided by the user has been accepted and is
     // now used to encrypt sync data.  |bootstrap_token| is an opaque base64
     // encoded representation of the key generated by the accepted passphrase,
     // and is provided to the observer for persistence purposes and use in a
     // future initialization of sync (e.g. after restart).
     virtual void OnPassphraseAccepted(const std::string& bootstrap_token) = 0;
 
     // Called when initialization is complete to the point that SyncManager can
     // process changes. This does not necessarily mean authentication succeeded
@@ skipping 204 matching lines @@
  private:
   // An opaque pointer to the nested private class.
   SyncInternal* data_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncManager);
 };
 
 }  // namespace sync_api
 
 #endif  // CHROME_BROWSER_SYNC_ENGINE_SYNCAPI_H_