Fix typo in comment: s/trail/trial/.

Change-Id: Ia412350582a5a6002d5a85797746d7d09594c2e4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2583042
Auto-Submit: Chris Fredrickson <cfredric@chromium.org>
Commit-Queue: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#836256}

base/feature_list.h

@@ -142,8 +142,8 @@ class BASE_EXPORT FeatureList {
   // a list entry has the format "FeatureName<TrialName" then this
   // initialization will also associate the feature state override with the
   // named field trial, if it exists. If a list entry has the format
-  // "FeatureName:k1/v1/k2/v2", "FeatureName<TrailName:k1/v1/k2/v2" or
-  // "FeatureName<TrailName.GroupName:k1/v1/k2/v2" then this initialization will
+  // "FeatureName:k1/v1/k2/v2", "FeatureName<TrialName:k1/v1/k2/v2" or
+  // "FeatureName<TrialName.GroupName:k1/v1/k2/v2" then this initialization will
   // also associate the feature state override with the named field trial and
   // its params. If the feature params part is provided but trial and/or group
   // isn't, this initialization will also create a synthetic trial, named