[sync] Automatic bootstrapping of Sync on Win 8 from cached credentials

chrome/browser/sync/profile_sync_service.h

Index: chrome/browser/sync/profile_sync_service.h
diff --git a/chrome/browser/sync/profile_sync_service.h b/chrome/browser/sync/profile_sync_service.h
index ef5eff0c9382fa1936b18ef0a068a38efb8e531f..48690578b79a8b6ab10cf77bfc69b930cb61931c 100644
--- a/chrome/browser/sync/profile_sync_service.h
+++ b/chrome/browser/sync/profile_sync_service.h
@@ -56,6 +56,7 @@ namespace sessions { class SyncSessionSnapshot; }
 
 namespace syncer {
 class BaseTransaction;
+class CredentialCacheService;
 struct SyncCredentials;
 struct UserShare;
 }
@@ -515,6 +516,9 @@ class ProfileSyncService : public browser_sync::SyncFrontend,
   const GURL& sync_service_url() const { return sync_service_url_; }
   bool auto_start_enabled() const { return auto_start_enabled_; }
   SigninManager* signin() const { return signin_; }
+  base::WeakPtr<browser_sync::SyncPrefs> sync_prefs() {
+    return sync_prefs_.AsWeakPtr();

[Andrew T Wilson (Slow), 2012/07/20 01:04:05]

In the past, people who need to access SyncPrefs have just instantiated new
instances. Is there a reason we need to expose our internal instance here?

[Raghu Simha, 2012/07/20 23:35:22]

I was under the (false) impression that only one SyncPrefs object could safely
be created. I've changed this to a local variable in CredentialCacheService.

+  }
 
   // Stops the sync backend and sets the flag for suppressing sync startup.
   void StopAndSuppress();
@@ -613,6 +617,17 @@ class ProfileSyncService : public browser_sync::SyncFrontend,
   friend class TestProfileSyncService;
   FRIEND_TEST_ALL_PREFIXES(ProfileSyncServiceTest, InitialState);
 
+  // Returns true if we are running on Windows 8, the user is not signed in to
+  // sync, sync is not disabled by policy, and startup is not suppressed.
+  // Used to prevent the user from having to sign in twice with the same account
+  // on Metro and Desktop Chrome.
+  bool ShouldInitializeCredentialCacheService();
+
+  // Returns true if we are running on Windows 8, the credential cache service
+  // is up and running, and credentials were successfully loaded from the
+  // alternate profile.
+  bool LoadedCachedCredentials();
+
   // Starts up sync if it is not suppressed and preconditions are met.
   // Called from Initialize() and UnsuppressAndStart().
   void TryStart();
@@ -816,6 +831,9 @@ class ProfileSyncService : public browser_sync::SyncFrontend,
   // Factory the backend will use to build the SyncManager.
   syncer::SyncManagerFactory sync_manager_factory_;
 
+  // Used to share sync credentials between Metro and Desktop on Windows 8.
+  syncer::CredentialCacheService* credential_cache_service_;
+
   DISALLOW_COPY_AND_ASSIGN(ProfileSyncService);
 };