Back out changeset 905ba2a1095a (bug 597525) because it breaks accessibility tests

content/html/content/src/nsHTMLTextAreaElement.cpp

@@ -593,6 +593,9 @@ nsHTMLTextAreaElement::SetValueChanged(PRBool aValueChanged)
   PRBool previousValue = mValueChanged;
 
   mValueChanged = aValueChanged;
+  if (!aValueChanged && !mState->IsEmpty()) {
+    mState->EmptyValue();
+  }
 
   if (mValueChanged != previousValue) {
     nsEventStates states = NS_EVENT_STATE_MOZ_UI_VALID |

content/html/content/src/nsTextEditorState.cpp

@@ -1718,7 +1718,9 @@ nsTextEditorState::GetValue(nsAString& aValue, PRBool aIgnoreWrap) const
       mCachedValue.Truncate();
     }
   } else {
-    if (mValue) {
+    if (!mTextCtrlElement->ValueChanged() || !mValue) {
+      mTextCtrlElement->GetDefaultValueFromContent(aValue);
+    } else {
       aValue = NS_ConvertUTF8toUTF16(*mValue);
     }
   }

content/html/content/src/nsTextEditorState.h

@@ -158,6 +158,8 @@ public:
 
   void SetValue(const nsAString& aValue, PRBool aUserInput);
   void GetValue(nsAString& aValue, PRBool aIgnoreWrap) const;
+  void EmptyValue() { if (mValue) mValue->Truncate(); }
+  PRBool IsEmpty() const { return mValue ? mValue->IsEmpty() : PR_TRUE; }
 
   nsresult CreatePlaceholderNode();