Bug 1362119 - part 1 - Moving dom/base/Script{Loader,Element}.* in dom/script, r=ehsan

This patch does these things:

1. it moves nsScriptElement, nsScriptLoader, ScriptSettings, nsIScriptElement
   and nsIScriptLoaderObserver in dom/script
2. it renames nsScriptElement to mozilla::dom::ScriptElement
3. it renames nsScriptLaoder to mozilla::dom::ScriptLoader

dom/html/HTMLScriptElement.h

@@ -8,16 +8,16 @@
 #define mozilla_dom_HTMLScriptElement_h
 
 #include "nsIDOMHTMLScriptElement.h"
-#include "nsScriptElement.h"
 #include "nsGenericHTMLElement.h"
 #include "mozilla/Attributes.h"
+#include "mozilla/dom/ScriptElement.h"
 
 namespace mozilla {
 namespace dom {
 
 class HTMLScriptElement final : public nsGenericHTMLElement,
                                 public nsIDOMHTMLScriptElement,
-                                public nsScriptElement
+                                public ScriptElement
 {
 public:
   using Element::GetText;
@@ -97,7 +97,8 @@ protected:
   virtual ~HTMLScriptElement();
 
   virtual JSObject* WrapNode(JSContext *aCx, JS::Handle<JSObject*> aGivenProto) override;
-  // nsScriptElement
+
+  // ScriptElement
   virtual bool HasScriptContent() override;
 };