Collapse the API surface on WebInputEvent via accessor functions.

chrome/browser/page_load_metrics/user_input_tracker_unittest.cc

Index: chrome/browser/page_load_metrics/user_input_tracker_unittest.cc
diff --git a/chrome/browser/page_load_metrics/user_input_tracker_unittest.cc b/chrome/browser/page_load_metrics/user_input_tracker_unittest.cc
index 751eb2a273f80e5b2c3936d9aab3e91429c5e928..b44277204b2c4335c6dfb7e9fe7824b5cd7bb6e3 100644
--- a/chrome/browser/page_load_metrics/user_input_tracker_unittest.cc
+++ b/chrome/browser/page_load_metrics/user_input_tracker_unittest.cc
@@ -210,7 +210,7 @@ TEST_F(UserInputTrackerTest, RateLimit) {
   // DCHECK in OnInputEvent verifies that we don't exceed the expected capacity.
   for (size_t i = 0; i < kTooManyEntries; ++i) {
     tracker.OnInputEvent(e);
-    e.setTimeStampSeconds(e.timeStampSeconds +
+    e.setTimeStampSeconds(e.timeStampSeconds() +
                           base::TimeDelta::FromMilliseconds(1).InSecondsF());
   }