Support placeholder text in NativeTextfieldViews.

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 2243e15f7978cfe4795aa888ed642463a332d315..4936ebf7ca859a14e210640d95993db71ba3ba75 100644
--- a/ui/views/controls/textfield/textfield.cc
+++ b/ui/views/controls/textfield/textfield.cc
@@ -29,6 +29,9 @@
 
 namespace views {
 
+// Default placeholder text color.
+const SkColor kDefaultPlaceholderTextColor = SK_ColorLTGRAY;
+
 // static
 const char Textfield::kViewClassName[] = "views/Textfield";
 
@@ -51,6 +54,7 @@ Textfield::Textfield()
       initialized_(false),
       horizontal_margins_were_set_(false),
       vertical_margins_were_set_(false),
+      placeholder_text_color_(kDefaultPlaceholderTextColor),
       text_input_type_(ui::TEXT_INPUT_TYPE_TEXT) {
   set_focusable(true);
 }
@@ -71,6 +75,7 @@ Textfield::Textfield(StyleFlags style)
       initialized_(false),
       horizontal_margins_were_set_(false),
       vertical_margins_were_set_(false),
+      placeholder_text_color_(kDefaultPlaceholderTextColor),
       text_input_type_(ui::TEXT_INPUT_TYPE_TEXT) {
   set_focusable(true);
   if (IsObscured())