First pass at cleaning up html lib warnings from the analyzer.

tools/dom/templates/html/impl/impl_WebGLRenderingContext.darttemplate

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of $LIBRARYNAME;
 
 $(ANNOTATIONS)class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
 $!MEMBERS
 
   /**
@@ skipping 49 matching lines @@
    *
    * [data] can be either an [ImageElement], a
    * [CanvasElement], a [VideoElement], or an [ImageData] object.
    *
    * To use [texSubImage2d] with a TypedData object, use [texSubImage2dTyped].
    *
    */
 $if DART2JS
   @JSName('texSubImage2D')
   void texSubImage2DUntyped(int targetTexture, int levelOfDetail,
-      int internalFormat, int format, int type, data) native;
+      int xOffset, int yOffset, int format, int type, data) native;
 $else
   void texSubImage2DUntyped(int targetTexture, int levelOfDetail, 
-      int internalFormat, int format, int type, data) {
-    texSubImage2D(targetTexture, levelOfDetail, internalFormat,
+      int xOffset, int yOffset, int format, int type, data) {
+    texSubImage2D(targetTexture, levelOfDetail, xOffset, yOffset,
         format, type, data);
   }
 $endif
 
   /**
    * Updates a sub-rectangle of the currently bound texture to [data].
    */
 $if DART2JS
   @JSName('texSubImage2D')
   void texSubImage2DTyped(int targetTexture, int levelOfDetail,
-      int internalFormat, int width, int height, int border, int format,
+      int xOffset, int yOffset, int width, int height, int border, int format,
       int type, TypedData data) native;
 $else
   void texSubImage2DTyped(int targetTexture, int levelOfDetail,
-      int internalFormat, int width, int height, int border, int format,
+      int xOffset, int yOffset, int width, int height, int format,
       int type, TypedData data) {
-    texSubImage2D(targetTexture, levelOfDetail, internalFormat,
-        width, height, border, format, type, data);
+    texSubImage2D(targetTexture, levelOfDetail, xOffset, yOffset,
+        width, height, format, type, data);
   }
 $endif
 }