Make uneditable when readonly

views/controls/textfield/textfield.h

Index: views/controls/textfield/textfield.h
diff --git a/views/controls/textfield/textfield.h b/views/controls/textfield/textfield.h
index e468423e8bb49329c1d352cddf633f4880efdc04..90c8139e4b00f3abcbe8e121a8b226b039987e4a 100644
--- a/views/controls/textfield/textfield.h
+++ b/views/controls/textfield/textfield.h
@@ -36,9 +36,11 @@ class NativeTextfieldWrapper;
 
 // TextRange specifies the range of text in the Textfield.  This is
 // used to specify selected text and will be used to change the
-// attributes of characters in the textfield. The range preserves the
-// direction, and selecting from the end to the begining is considered
-// "reverse" order.
+// attributes of characters in the textfield. When this is used for
+// selection, the end is caret position, and the start is where
+// selection started.  The range preserves the direction, and
+// selecting from the end to the begining is considered "reverse"
+// order. (that is, start > end is reverse)
 class TextRange {
  public:
   TextRange() : start_(0), end_(0) {}