[sync] Enable sync credential caching by default for post-M22 builds

Sync credential caching is a Win 8 feature that allows Metro and Desktop
to share sync credentials under some circumstances. The feature is
slated to ship with M23, and was disabled for the M22 branch point.
Now that M22 has been branched off, it is time to re-enable the feature.

This patch turns on the feature by default, and provides users with the
"--disable-sync-credential-caching" flag if the feature must be disabled.

BUG=139712
TEST=Sign in on Win 8 and make sure that "Sync Credentials" is written to the default profile directory

Review URL: https://chromiumcodereview.appspot.com/10855063

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@151169 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/sync/credential_cache_service_factory_win.cc

@@ -61,11 +61,11 @@ bool CredentialCacheServiceFactory::ServiceIsCreatedWithProfile() {
 ProfileKeyedService* CredentialCacheServiceFactory::BuildServiceInstanceFor(
     Profile* profile) const {
   // Only instantiate a CredentialCacheService object if we are running in the
-  // default profile on Windows 8, and if credential caching is enabled.
+  // default profile on Windows 8, and if credential caching is not disabled.
   const CommandLine* command_line = CommandLine::ForCurrentProcess();
   if (base::win::GetVersion() >= base::win::VERSION_WIN8 &&
       IsDefaultProfile(profile) &&
-      command_line->HasSwitch(switches::kEnableSyncCredentialCaching)) {
+      !command_line->HasSwitch(switches::kDisableSyncCredentialCaching)) {
     return new syncer::CredentialCacheService(profile);
   }
   return NULL;

chrome/common/chrome_switches.cc

@@ -1522,9 +1522,9 @@ const char kUseMockKeychain[]               = "use-mock-keychain";
 // modification or removal.
 const char kDisableDesktopShortcuts[]       = "disable-desktop-shortcuts";
 
-// Enables sync credential caching on Windows 8.
+// Disables sync credential caching on Windows 8.
 // See chrome/browser/sync/credential_cache_service_win.h.
-const char kEnableSyncCredentialCaching[]    = "enable-sync-credential-caching";
+const char kDisableSyncCredentialCaching[]  = "disable-sync-credential-caching";
 
 // For the DelegateExecute verb handler to launch Chrome in metro mode on
 // Windows 8 and higher.  Used when relaunching metro Chrome.

chrome/common/chrome_switches.h

@@ -425,7 +425,7 @@ extern const char kUseMockKeychain[];
 
 #if defined(OS_WIN)
 extern const char kDisableDesktopShortcuts[];
-extern const char kEnableSyncCredentialCaching[];
+extern const char kDisableSyncCredentialCaching[];
 extern const char kForceImmersive[];
 extern const char kRelaunchShortcut[];
 extern const char kWaitForHandle[];