Mac: Add new accessibility attributes for textfields (and some for all views).

ui/views/controls/textfield/textfield.cc

Index: ui/views/controls/textfield/textfield.cc
diff --git a/ui/views/controls/textfield/textfield.cc b/ui/views/controls/textfield/textfield.cc
index 19e5c2ca689acbd6ab7cc7c045d7ef6bdd536c3e..1f41fb769b5d25e8bd1b67a454f4ef3e2336b1c2 100644
--- a/ui/views/controls/textfield/textfield.cc
+++ b/ui/views/controls/textfield/textfield.cc
@@ -913,6 +913,8 @@ void Textfield::GetAccessibleState(ui::AXViewState* state) {
   } else {
     state->value = text();
   }
+  state->placeholder = GetPlaceholderText();
+
   const gfx::Range range = GetSelectedRange();
   state->selection_start = range.start();
   state->selection_end = range.end();