Bug 570893 - Only re-enable the form controls when reload, not re-disable it, r=bz

With this patch, the disabled state is still kept in the nsPresState,
but we will only honor that if the state saved asks as to re-enable the
control.

The behavior is changed so that controls disabled by JavaScript will be
kept enabled as the JavaScript world gets reloaded.

MozReview-Commit-ID: 6PchHfx6KYX

dom/html/HTMLButtonElement.cpp

@@ -476,8 +476,8 @@ HTMLButtonElement::SaveState()
 bool
 HTMLButtonElement::RestoreState(nsPresState* aState)
 {
-  if (aState && aState->IsDisabledSet()) {
-    SetDisabled(aState->GetDisabled());
+  if (aState && aState->IsDisabledSet() && !aState->GetDisabled()) {
+    SetDisabled(false);
   }
 
   return false;