Ensure tests have an active task runner

components/data_reduction_proxy/content/browser/data_reduction_proxy_message_filter_unittest.cc

 // Copyright 2015 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 "components/data_reduction_proxy/content/browser/data_reduction_proxy_message_filter.h"
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_config_test_utils.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_test_utils.h"
@@ skipping 20 matching lines @@
  protected:
   DataReductionProxyMessageFilter* message_filter() const {
     return message_filter_.get();
   }
 
   MockDataReductionProxyConfig* config() const {
     return test_context_->mock_config();
   }
 
  private:
+  base::MessageLoopForIO message_loop_;
   scoped_ptr<DataReductionProxyTestContext> test_context_;
   scoped_refptr<DataReductionProxyMessageFilter> message_filter_;
 };
 
 TEST_F(DataReductionProxyMessageFilterTest, TestOnIsDataReductionProxy) {
   net::HostPortPair proxy_server =
       net::HostPortPair::FromString("www.google.com:443");
   bool is_data_reduction_proxy = false;
   EXPECT_CALL(*config(), IsDataReductionProxy(testing::_, nullptr))
       .Times(1)
       .WillOnce(testing::Return(true));
   message_filter()->OnIsDataReductionProxy(proxy_server,
                                            &is_data_reduction_proxy);
   EXPECT_TRUE(is_data_reduction_proxy);
 
   EXPECT_CALL(*config(), IsDataReductionProxy(testing::_, nullptr))
       .Times(1)
       .WillOnce(testing::Return(false));
   message_filter()->OnIsDataReductionProxy(proxy_server,
                                            &is_data_reduction_proxy);
   EXPECT_FALSE(is_data_reduction_proxy);
 }
 
 }  // namespace data_reduction_proxy