Add text field change handling for autofill preview in textarea element.

public/web/WebAutofillClient.h

Index: public/web/WebAutofillClient.h
diff --git a/public/web/WebAutofillClient.h b/public/web/WebAutofillClient.h
index 8b13aa0c156330d76999cbcbbf4797d5bb032231..347b6926bdce7a4b176f961c6dc0b63ef2191059 100644
--- a/public/web/WebAutofillClient.h
+++ b/public/web/WebAutofillClient.h
@@ -33,6 +33,7 @@
 
 namespace blink {
 
+class WebFormControlElement;
 class WebFormElement;
 class WebFrame;
 class WebInputElement;
@@ -48,7 +49,7 @@ public:
 
     // These methods are called when the users edits a text-field.
     virtual void textFieldDidEndEditing(const WebInputElement&) { }
-    virtual void textFieldDidChange(const WebInputElement&) { }
+    virtual void textFieldDidChange(const WebFormControlElement&) { }

[tkent, 2014/03/04 00:15:56]

This will break build because Chromium has "textFieldDidChange(const
WebInputElement&) OVERRIDE".  Please *add* textFieldDidChange(const
WebFormControlElement&).

[jamesr, 2014/03/04 00:26:33]

If so then the bug is the OVERRIDE annotation on the chromium side. 
Implementations of cross-repo APIs should *never* have OVERRIDE annotations.

[ziran.sun, 2014/03/04 12:12:40]

Do you mean add "textFieldDidChange(const
WebInputElement&)" here?

[ziran.sun, 2014/03/04 12:12:40]

In the chromium side code for this bug, we removed OVERRIDE for both 
textFieldDidChange(const WebInputElement&) and
textFieldDidChange(const WebFormControlElement&)

The end target though is to replace textFieldDidChange(const WebInputElement&)
with textFieldDidChange(const WebInputElement&). Reason for keeping both for the
moment is due to the Blink roll delay.  

So once both Blink and Chromium side code are merged in, we'll remove
textFieldDidChange(const WebInputElement&). Then we put OVERRIDE on
textFieldDidChange(const WebFormControlElement&) - this is the stage I'm not
sure. If I understand correctly, your mean OVERRIDE shouldn't be used here at
all? 

     virtual void textFieldDidReceiveKeyDown(const WebInputElement&, const WebKeyboardEvent&) { }
     // This is called when a datalist indicator is clicked.
     virtual void openTextDataListChooser(const WebInputElement&) { }