Prepare for syncing profiles (microsoft#160455)

- First step of making UserDataSyncService profiles aware

Author: sandy081

src/vs/platform/userDataSync/common/abstractSynchronizer.ts

@@ -676,8 +676,15 @@ export abstract class AbstractSynchroniser extends Disposable implements IUserDa
 	protected async updateRemoteUserData(content: string, ref: string | null): Promise<IRemoteUserData> {
 		const machineId = await this.currentMachineIdPromise;
 		const syncData: ISyncData = { version: this.version, machineId, content };
-		ref = await this.userDataSyncStoreService.write(this.resource, JSON.stringify(syncData), ref, undefined, this.syncHeaders);
-		return { ref, syncData };
+		try {
+			ref = await this.userDataSyncStoreService.write(this.resource, JSON.stringify(syncData), ref, undefined, this.syncHeaders);
+			return { ref, syncData };
+		} catch (error) {
+			if (error instanceof UserDataSyncError && error.code === UserDataSyncErrorCode.TooLarge) {
+				error = new UserDataSyncError(error.message, error.code, this.resource);
+			}
+			throw error;
+		}
 	}
 
 	protected async backupLocal(content: string): Promise<void> {