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

Source/web/WebFormControlElement.cpp

Index: Source/web/WebFormControlElement.cpp
diff --git a/Source/web/WebFormControlElement.cpp b/Source/web/WebFormControlElement.cpp
index d833087906325288ae0a1ca59221e875b3841718..527db7713b3a61050cd5921cfee3971103d6ec93 100644
--- a/Source/web/WebFormControlElement.cpp
+++ b/Source/web/WebFormControlElement.cpp
@@ -33,6 +33,9 @@
 
 #include "core/html/HTMLFormControlElement.h"
 #include "core/html/HTMLFormElement.h"
+#include "core/html/HTMLInputElement.h"
+#include "core/html/HTMLTextAreaElement.h"
+
 #include "wtf/PassRefPtr.h"
 
 using namespace WebCore;
@@ -79,6 +82,33 @@ WebString WebFormControlElement::nameForAutofill() const
     return constUnwrap<HTMLFormControlElement>()->nameForAutofill();
 }
 
+WebString WebFormControlElement::editingValue() const
+{
+    if (m_private->hasTagName(HTMLNames::inputTag))
+        return constUnwrap<HTMLInputElement>()->innerTextValue();
+    if (m_private->hasTagName(HTMLNames::textareaTag))
+        return constUnwrap<HTMLTextAreaElement>()->innerTextValue();
+    return WebString();
+}
+
+int WebFormControlElement::selectionStart() const
+{
+    if (m_private->hasTagName(HTMLNames::inputTag))
+        return constUnwrap<HTMLInputElement>()->selectionStart();
+    if (m_private->hasTagName(HTMLNames::textareaTag))
+        return constUnwrap<HTMLTextAreaElement>()->selectionStart();
+    return 0;
+}
+
+int WebFormControlElement::selectionEnd() const
+{
+    if (m_private->hasTagName(HTMLNames::inputTag))
+        return constUnwrap<HTMLInputElement>()->selectionEnd();
+    if (m_private->hasTagName(HTMLNames::textareaTag))
+        return constUnwrap<HTMLTextAreaElement>()->selectionEnd();
+    return 0;
+}
+
 WebFormElement WebFormControlElement::form() const
 {
     return WebFormElement(constUnwrap<HTMLFormControlElement>()->form());