Ensure OAuth2TokenServiceRequest::Core is destroyed on owner thread.

google_apis/gaia/oauth2_token_service_request_unittest.cc

Index: google_apis/gaia/oauth2_token_service_request_unittest.cc
diff --git a/google_apis/gaia/oauth2_token_service_request_unittest.cc b/google_apis/gaia/oauth2_token_service_request_unittest.cc
index b62700694c48b7a6965b9dd8fcdd989502576505..0a86cfd0e2da9a82151574c28ab9747b8bd8694c 100644
--- a/google_apis/gaia/oauth2_token_service_request_unittest.cc
+++ b/google_apis/gaia/oauth2_token_service_request_unittest.cc
@@ -146,6 +146,7 @@ void MockOAuth2TokenService::InvalidateOAuth2Token(
 class OAuth2TokenServiceRequestTest : public testing::Test {
  public:
   virtual void SetUp() OVERRIDE;
+  virtual void TearDown() OVERRIDE;
 
  protected:
   class Provider : public OAuth2TokenServiceRequest::TokenServiceProvider {
@@ -177,6 +178,11 @@ void OAuth2TokenServiceRequestTest::SetUp() {
       new Provider(base::MessageLoopProxy::current(), oauth2_service_.get()));
 }
 
+void OAuth2TokenServiceRequestTest::TearDown() {
+  // Run the loop to execute any pending tasks that may free resources.
+  ui_loop_.RunUntilIdle();
+}
+
 OAuth2TokenServiceRequestTest::Provider::Provider(
     const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
     OAuth2TokenService* token_service)