An edit for SetText needs to be merged with previous edit for omnibox.

views/controls/textfield/textfield.cc

Index: views/controls/textfield/textfield.cc
diff --git a/views/controls/textfield/textfield.cc b/views/controls/textfield/textfield.cc
index 8775871be7790698994d2d2c731932f56788b798..c2bc1288fedce19c2eb80cf796579fbb8bef72fb 100644
--- a/views/controls/textfield/textfield.cc
+++ b/views/controls/textfield/textfield.cc
@@ -289,6 +289,11 @@ void Textfield::ClearAllTextStyles() {
   native_wrapper_->ClearAllTextStyles();
 }
 
+void Textfield::ClearEditHistory() {
+  DCHECK(native_wrapper_);
+  native_wrapper_->ClearEditHistory();
+}
+
 void Textfield::SetAccessibleName(const string16& name) {
   accessible_name_ = name;
 }