Fix for bug 815158 (Make HTMLElement.ontouch* work with tristate dom.w3c_touch_events.enabled). r=bz.

--HG--
extra : rebase_source : 878d559d1a57ad69bdac7bea682ea344ecdea96a

content/html/content/src/nsGenericHTMLElement.cpp

@@ -100,6 +100,7 @@
 #include "mozilla/dom/BindingUtils.h"
 #include "mozilla/ErrorResult.h"
 #include "nsHTMLDocument.h"
+#include "nsDOMTouchEvent.h"
 
 using namespace mozilla;
 using namespace mozilla::dom;
@@ -2906,6 +2907,24 @@ nsGenericHTMLElement::IsLabelable() const
          Tag() == nsGkAtoms::meter;
 }
 
+// static
+bool
+nsGenericHTMLElement::PrefEnabled()
+{
+  // This is a bit of a hack because we don't support non-bool prefs to enable
+  // properties. This function will be called every time a HTMLElement interface
+  // prototype object is created. The first time this is called we set a boolean
+  // pref (dom.w3c_touch_events.expose) which controls the touch event
+  // properties on HTMLElement.
+  static bool sDidSetPref = false;
+  if (!sDidSetPref) {
+    sDidSetPref = true;
+    Preferences::SetBool("dom.w3c_touch_events.expose",
+                         nsDOMTouchEvent::PrefEnabled());
+  }
+  return true;
+}
+
 //----------------------------------------------------------------------
 
 nsGenericHTMLFormElement::nsGenericHTMLFormElement(already_AddRefed<nsINodeInfo> aNodeInfo)

content/html/content/src/nsGenericHTMLElement.h

@@ -715,6 +715,8 @@ public:
 
   virtual bool IsLabelable() const;
 
+  static bool PrefEnabled();
+
 protected:
   /**
    * Add/remove this element to the documents name cache

dom/webidl/HTMLElement.webidl

@@ -15,6 +15,7 @@
 interface DOMStringMap;
 interface HTMLMenuElement;
 
+[PrefControlled]
 interface HTMLElement : Element {
   // metadata attributes
            attribute DOMString title;
@@ -207,17 +208,17 @@ interface HTMLElement : Element {
   [SetterThrows]
            attribute EventHandler onwheel;
 
-  [SetterThrows,Pref="dom.w3c_touch_events.enabled"]
+  [SetterThrows,Pref="dom.w3c_touch_events.expose"]
            attribute EventHandler ontouchstart;
-  [SetterThrows,Pref="dom.w3c_touch_events.enabled"]
+  [SetterThrows,Pref="dom.w3c_touch_events.expose"]
            attribute EventHandler ontouchend;
-  [SetterThrows,Pref="dom.w3c_touch_events.enabled"]
+  [SetterThrows,Pref="dom.w3c_touch_events.expose"]
            attribute EventHandler ontouchmove;
-  [SetterThrows,Pref="dom.w3c_touch_events.enabled"]
+  [SetterThrows,Pref="dom.w3c_touch_events.expose"]
            attribute EventHandler ontouchenter;
-  [SetterThrows,Pref="dom.w3c_touch_events.enabled"]
+  [SetterThrows,Pref="dom.w3c_touch_events.expose"]
            attribute EventHandler ontouchleave;
-  [SetterThrows,Pref="dom.w3c_touch_events.enabled"]
+  [SetterThrows,Pref="dom.w3c_touch_events.expose"]
            attribute EventHandler ontouchcancel;
 
   [SetterThrows]