Bug 1497981 - Simplify ImageLoader::LoadImage. r=heycam

Has a single caller, from which we pass the arguments. We can just avoid that.

Differential Revision: https://phabricator.services.mozilla.com/D8276

layout/style/nsCSSValue.h

@@ -155,6 +155,8 @@ public:
 
   uint64_t LoadID() const { return mLoadID; }
 
+  CORSMode CorsMode() const { return mCORSMode; }
+
 private:
   // mURI stores the lazily resolved URI.  This may be null if the URI is
   // invalid, even once resolved.