Add WARN_UNUSED_RESULT to base::Time methods that return bool.

components/data_reduction_proxy/core/browser/data_reduction_proxy_compression_stats_unittest.cc

 // Copyright 2014 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/core/browser/data_reduction_proxy_compression_stats.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <string>
@@ skipping 96 matching lines @@
 
 // The initial last update time used in test. There is no leap second a few
 // days around this time used in the test.
 // Note: No time zone is specified. Local time will be assumed by
 // base::Time::FromString below.
 const char kLastUpdateTime[] = "Wed, 18 Sep 2013 03:45:26";
 
 class DataReductionProxyCompressionStatsTest : public testing::Test {
  protected:
   DataReductionProxyCompressionStatsTest() {
-    base::Time::FromString(kLastUpdateTime, &now_);
+    EXPECT_TRUE(base::Time::FromString(kLastUpdateTime, &now_));
   }
 
   void SetUp() override {
     drp_test_context_ = DataReductionProxyTestContext::Builder().Build();
 
     compression_stats_.reset(new DataReductionProxyCompressionStats(
         data_reduction_proxy_service(), pref_service(), base::TimeDelta()));
   }
 
   void ResetCompressionStatsWithDelay(const base::TimeDelta& delay) {
@@ skipping 1228 matching lines @@
   expected_data_usage =
       base::MakeUnique<std::vector<data_reduction_proxy::DataUsageBucket>>(
           kNumExpectedBuckets);
   DataUsageLoadVerifier verifier2(std::move(expected_data_usage));
   LoadHistoricalDataUsage(base::Bind(&DataUsageLoadVerifier::OnLoadDataUsage,
                                      base::Unretained(&verifier2)));
   base::RunLoop().RunUntilIdle();
 }
 
 }  // namespace data_reduction_proxy