[Sync] Add sync api support for context changes

chrome/browser/sync/glue/shared_change_processor.cc

 // Copyright (c) 2012 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.
 
 #include "chrome/browser/sync/glue/shared_change_processor.h"
 
 #include "chrome/browser/sync/glue/generic_change_processor.h"
 #include "chrome/browser/sync/profile_sync_components_factory.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "content/public/browser/browser_thread.h"
@@ skipping 124 matching lines @@
   if (disconnected_) {
     syncer::SyncError error(FROM_HERE,
                             syncer::SyncError::DATATYPE_ERROR,
                             "Change processor disconnected.",
                             type_);
     return error;
   }
   return generic_change_processor_->GetAllSyncDataReturnError(type, data);
 }
 
+syncer::SyncError SharedChangeProcessor::UpdateDataTypeContext(
+    syncer::ModelType type,
+    const std::string& context) {
+  DCHECK(backend_loop_.get());
+  DCHECK(backend_loop_->BelongsToCurrentThread());
+  AutoLock lock(monitor_lock_);
+  if (disconnected_) {
+    syncer::SyncError error(FROM_HERE,
+                            syncer::SyncError::DATATYPE_ERROR,
+                            "Change processor disconnected.",
+                            type_);
+    return error;
+  }
+  return generic_change_processor_->UpdateDataTypeContext(type, context);
+}
+
 bool SharedChangeProcessor::SyncModelHasUserCreatedNodes(bool* has_nodes) {
   DCHECK(backend_loop_.get());
   DCHECK(backend_loop_->BelongsToCurrentThread());
   AutoLock lock(monitor_lock_);
   if (disconnected_) {
     LOG(ERROR) << "Change processor disconnected.";
     return false;
   }
   return generic_change_processor_->SyncModelHasUserCreatedNodes(
       type_, has_nodes);
@@ skipping 32 matching lines @@
     return error_handler_->CreateAndUploadError(location, message, type_);
   } else {
     return syncer::SyncError(location,
                              syncer::SyncError::DATATYPE_ERROR,
                              message,
                              type_);
   }
 }
 
 }  // namespace browser_sync