[Sync] Make BackendMigrator not wait for full sync cycles

chrome/browser/sync/profile_sync_service_harness.h

Index: chrome/browser/sync/profile_sync_service_harness.h
diff --git a/chrome/browser/sync/profile_sync_service_harness.h b/chrome/browser/sync/profile_sync_service_harness.h
index 5ec8a444deb00c7ee0e4e9d85378ca9423dc605f..fcaa603d9d2b463ee2598e706e993b312148ff46 100644
--- a/chrome/browser/sync/profile_sync_service_harness.h
+++ b/chrome/browser/sync/profile_sync_service_harness.h
@@ -10,6 +10,8 @@
 #include <vector>
 
 #include "base/basictypes.h"
+#include "base/compiler_specific.h"
+#include "chrome/browser/sync/backend_migrator.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/browser/sync/profile_sync_service_observer.h"
 #include "chrome/browser/sync/retry_verifier.h"
@@ -28,7 +30,9 @@ namespace browser_sync {
 // profile passed to it on construction and automates certain things like setup
 // and authentication. It provides ways to "wait" adequate periods of time for
 // several clients to get to the same state.
-class ProfileSyncServiceHarness : public ProfileSyncServiceObserver {
+class ProfileSyncServiceHarness
+    : public ProfileSyncServiceObserver,
+      public browser_sync::MigrationObserver {
  public:
   ProfileSyncServiceHarness(Profile* profile,
                             const std::string& username,
@@ -58,7 +62,10 @@ class ProfileSyncServiceHarness : public ProfileSyncServiceObserver {
   bool SetupSync(const syncable::ModelTypeSet& synced_datatypes);
 
   // ProfileSyncServiceObserver implementation.
-  virtual void OnStateChanged();
+  virtual void OnStateChanged() OVERRIDE;
+
+  // MigrationObserver implementation.
+  virtual void OnMigrationStateChange() OVERRIDE;
 
   // Blocks the caller until the sync backend host associated with this harness
   // has been initialized.  Returns true if the wait was successful.
@@ -73,15 +80,6 @@ class ProfileSyncServiceHarness : public ProfileSyncServiceObserver {
   // since the previous one.  Returns true if a sync cycle has completed.
   bool AwaitSyncCycleCompletion(const std::string& reason);
 
-  // Blocks the caller until this harness has completed a single sync
-  // cycle, even if we're already synced.  Returns true if a sync
-  // cycle has completed.
-  //
-  // TODO(akalin): This is only used by some migration tests, pending
-  // the fix for http://crbug.com/92928.  Remove this once that is
-  // fixed.
-  bool AwaitNextSyncCycleCompletion(const std::string& reason);
-
   // Blocks the caller until the sync has been disabled for this client. Returns
   // true if sync is disabled.
   bool AwaitSyncDisabled(const std::string& reason);
@@ -89,6 +87,9 @@ class ProfileSyncServiceHarness : public ProfileSyncServiceObserver {
   // Blocks the caller until exponential backoff has been verified to happen.
   bool AwaitExponentialBackoffVerification();
 
+  // Blocks until the given set of data types are migrated.
+  bool AwaitMigration(const syncable::ModelTypeSet& expected_migrated_types);
+
   // Blocks the caller until this harness has observed that the sync engine
   // has downloaded all the changes seen by the |partner| harness's client.
   bool WaitUntilTimestampMatches(
@@ -213,6 +214,12 @@ class ProfileSyncServiceHarness : public ProfileSyncServiceObserver {
     // backoffs are triggered correctly.
     WAITING_FOR_EXPONENTIAL_BACKOFF_VERIFICATION,
 
+    // The sync client is waiting for migration to start.
+    WAITING_FOR_MIGRATION_TO_START,
+
+    // The sync client is waiting for migration to finish.
+    WAITING_FOR_MIGRATION_TO_FINISH,
+
     // The client verification is complete. We don't care about the state of
     // the syncer any more.
     WAITING_FOR_NOTHING,
@@ -232,6 +239,11 @@ class ProfileSyncServiceHarness : public ProfileSyncServiceObserver {
     NUMBER_OF_STATES,
   };
 
+  // Listen to migration events if the migrator has been initialized
+  // and we're not already listening.  Returns true if we started
+  // listening.
+  bool TryListeningToMigrationEvents();
+
   // Called from the observer when the current wait state has been completed.
   void SignalStateCompleteWithNextState(WaitState next_state);
 
@@ -246,13 +258,12 @@ class ProfileSyncServiceHarness : public ProfileSyncServiceObserver {
   bool AwaitStatusChangeWithTimeout(int timeout_milliseconds,
                                     const std::string& reason);
 
-  // Used by AwaitSyncCycleCompletion() and
-  // AwaitNextSyncCycleCompletion().
-  bool AwaitSyncCycleCompletionHelper(const std::string& reason);
-
   // Returns true if the sync client has no unsynced items.
   bool IsSynced();
 
+  // Returns true if there is a backend migration in progress.
+  bool HasPendingBackendMigration();
+
   // Returns true if this client has downloaded all the items that the
   // other client has.
   bool MatchesOtherClient(ProfileSyncServiceHarness* partner);
@@ -290,6 +301,14 @@ class ProfileSyncServiceHarness : public ProfileSyncServiceObserver {
   std::string username_;
   std::string password_;
 
+  // The current set of data types pending migration.  Used by
+  // AwaitMigration().
+  syncable::ModelTypeSet pending_migration_types_;
+
+  // The set of data types that have undergone migration.  Used by
+  // AwaitMigration().
+  syncable::ModelTypeSet migrated_types_;
+
   // Used for logging.
   const std::string profile_debug_name_;