Bug 1343037 part 5. Make <textarea> behave more like <input type=text> in terms of reset behavior. r=ehsan

In particular this ensures that our ValueChanged() is correctly set to false
when we call SetValue() on our editor state with our default value.  We will be
relying on this very shortly.

MozReview-Commit-ID: AIIIHwfQPQE

dom/html/HTMLTextAreaElement.cpp

@@ -324,11 +324,14 @@ nsresult
 HTMLTextAreaElement::SetValueInternal(const nsAString& aValue,
                                       uint32_t aFlags)
 {
-  // Need to set the value changed flag here, so that
-  // nsTextControlFrame::UpdateValueDisplay retrieves the correct value
-  // if needed.
-  SetValueChanged(true);
-  aFlags |= nsTextEditorState::eSetValue_Notify;
+  // Need to set the value changed flag here if our value has in fact changed
+  // (i.e. if eSetValue_Notify is in aFlags), so that
+  // nsTextControlFrame::UpdateValueDisplay retrieves the correct value if
+  // needed.
+  if (aFlags & nsTextEditorState::eSetValue_Notify) {
+    SetValueChanged(true);
+  }
+
   if (!mState.SetValue(aValue, aFlags)) {
     return NS_ERROR_OUT_OF_MEMORY;
   }
@@ -350,7 +353,8 @@ HTMLTextAreaElement::SetValue(const nsAString& aValue)
   GetValueInternal(currentValue, true);
 
   nsresult rv =
-    SetValueInternal(aValue, nsTextEditorState::eSetValue_ByContent);
+    SetValueInternal(aValue, nsTextEditorState::eSetValue_ByContent |
+                             nsTextEditorState::eSetValue_Notify);
   NS_ENSURE_SUCCESS(rv, rv);
 
   if (mFocusedValue.Equals(currentValue)) {
@@ -363,7 +367,9 @@ HTMLTextAreaElement::SetValue(const nsAString& aValue)
 NS_IMETHODIMP 
 HTMLTextAreaElement::SetUserInput(const nsAString& aValue)
 {
-  return SetValueInternal(aValue, nsTextEditorState::eSetValue_BySetUserInput);
+  return SetValueInternal(aValue,
+                          nsTextEditorState::eSetValue_BySetUserInput |
+                          nsTextEditorState::eSetValue_Notify);
 }
 
 NS_IMETHODIMP
@@ -1043,10 +1049,11 @@ HTMLTextAreaElement::Reset()
   NS_ENSURE_SUCCESS(rv, rv);
   nsAutoString resetVal;
   GetDefaultValue(resetVal);
-  rv = SetValue(resetVal);
+  SetValueChanged(false);
+
+  rv = SetValueInternal(resetVal, nsTextEditorState::eSetValue_Internal);
   NS_ENSURE_SUCCESS(rv, rv);
 
-  SetValueChanged(false);
   return NS_OK;
 }