Add textfield internal padding from FocusableBorder.

ui/views/controls/textfield/textfield.h

Index: ui/views/controls/textfield/textfield.h
diff --git a/ui/views/controls/textfield/textfield.h b/ui/views/controls/textfield/textfield.h
index e06a3326c81c3241b6d12072d66752b72fa5981b..60767ab98ac90dbc3ff298d27438ecfbd7de2441 100644
--- a/ui/views/controls/textfield/textfield.h
+++ b/ui/views/controls/textfield/textfield.h
@@ -45,6 +45,9 @@ class VIEWS_EXPORT Textfield : public View,
   // The textfield's class name.
   static const char kViewClassName[];
 
+  // The preferred size of the padding to be used around textfield text.
+  static const int kTextPadding;
+
   // Returns the text cursor blink time in milliseconds, or 0 for no blinking.
   static size_t GetCaretBlinkMs();