[Cleanup] Fix a typo.

R=asvitkine@chromium.org

Bug: none
Change-Id: I4b4cdbd7d75d243818ddb3f4884b22f43e86de7a
Reviewed-on: https://chromium-review.googlesource.com/813281
Commit-Queue: Alexei Svitkine <asvitkine@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Cr-Commit-Position: refs/heads/master@{#522421}

components/variations/service/variations_service_unittest.cc

@@ -917,7 +917,7 @@ TEST_F(VariationsServiceTest, SafeMode_SuccessfulFetchClearsFailureStreaks) {
   fetcher->SetResponseString(response);
   service.OnURLFetchComplete(fetcher);
 
-  // Verify that the streaks were rest.
+  // Verify that the streaks were reset.
   EXPECT_EQ(0, prefs_.GetInteger(prefs::kVariationsCrashStreak));
   EXPECT_EQ(0, prefs_.GetInteger(prefs::kVariationsFailedToFetchSeedStreak));
 }