Use dictionaries for context creation attributes. Eliminate custom bindings.

LayoutTests/fast/canvas/canvas-context-attributes-default-value.html

Index: LayoutTests/fast/canvas/canvas-context-attributes-default-value.html
diff --git a/LayoutTests/fast/canvas/canvas-context-attributes-default-value.html b/LayoutTests/fast/canvas/canvas-context-attributes-default-value.html
index 46378c6ab9a95361f01a6958cfe0e6e7408e6b85..f23a5386bdb4eed9113967f5eeb84bfa48fe9e96 100644
--- a/LayoutTests/fast/canvas/canvas-context-attributes-default-value.html
+++ b/LayoutTests/fast/canvas/canvas-context-attributes-default-value.html
@@ -4,10 +4,14 @@
 <script src="../../resources/js-test.js"></script>
 <script>
 
-  var checkAttributes = {
+  var trueAttributes = {
     alpha : true,
   };
 
+  var falseAttributes = {
+    alpha : false,
+  };
+
   function testAttributes(expectedAttributes, checkValue) {
 
     if (arguments.length != 1 && arguments.length != 2)
@@ -37,15 +41,15 @@
 <script>
 
   debug("Testing default value:");
-  testAttributes(checkAttributes);
+  testAttributes(trueAttributes);
   debug("")
 
   debug("Testing undefined value:");
-  testAttributes(checkAttributes, undefined);
+  testAttributes(trueAttributes, undefined);
   debug("")
 
   debug("Testing null value:");
-  testAttributes(checkAttributes, null);
+  testAttributes(falseAttributes, null);
   debug("")
 
 </script>