recommend a EventHandler.Do()

Test: manually verified equivalence
Bug: N/A
Change-Id: I2a5abd5b1230ab1f1b5851672e80833c5d18d5c7

context.go

@@ -3648,7 +3648,7 @@ func (c *Context) SingletonName(singleton Singleton) string {
 	return ""
 }
 
-// WriteBuildFile writes the Ninja manifeset text for the generated build
+// WriteBuildFile writes the Ninja manifest text for the generated build
 // actions to w.  If this is called before PrepareBuildActions successfully
 // completes then ErrBuildActionsNotReady is returned.
 func (c *Context) WriteBuildFile(w io.StringWriter) error {

metrics/event_handler.go

@@ -62,6 +62,13 @@ func (h *EventHandler) Begin(name string) {
 	h.scopeStartTimes = append(h.scopeStartTimes, _now())
 }
 
+// Do wraps a function with calls to Begin() and End().
+func (h *EventHandler) Do(name string, f func()) {
+	h.Begin(name)
+	defer h.End(name)
+	f()
+}
+
 // End logs the end of an event. All events nested within this event must have
 // themselves been marked completed.
 func (h *EventHandler) End(name string) {