Add getter for EventHandler so its easier to mock

Test: m nothing
Change-Id: Ied338a25f12404ddc88c3b3cb7d7f2ff9ade3aab

context.go

@@ -992,7 +992,6 @@ func shouldVisitFile(c *Context, file *parser.File) (bool, []error) {
 	return true, []error{}
 }
 
-
 func (c *Context) ParseFileList(rootDir string, filePaths []string,
 	config interface{}) (deps []string, errs []error) {
 
@@ -4455,6 +4454,10 @@ func (c *Context) writeAllSingletonActions(nw *ninjaWriter) error {
 	return nil
 }
 
+func (c *Context) GetEventHandler() *metrics.EventHandler {
+	return c.EventHandler
+}
+
 func (c *Context) BeginEvent(name string) {
 	c.EventHandler.Begin(name)
 }