IDL: Null values should be converted for non-nullable dictionary members

LayoutTests/fast/canvas/canvas-hit-regions-basic-test.html

Index: LayoutTests/fast/canvas/canvas-hit-regions-basic-test.html
diff --git a/LayoutTests/fast/canvas/canvas-hit-regions-basic-test.html b/LayoutTests/fast/canvas/canvas-hit-regions-basic-test.html
index 4d8179ed4d3091345ec58743d56b5aaf4449e954..fc9ddfde3b1f5f5fb027a6fa8d38baa6582edf54 100644
--- a/LayoutTests/fast/canvas/canvas-hit-regions-basic-test.html
+++ b/LayoutTests/fast/canvas/canvas-hit-regions-basic-test.html
@@ -77,19 +77,15 @@
   debug("NotSupportedError exception tests");
   shouldThrow("context.addHitRegion()");
   shouldThrow("context.addHitRegion({ id : '' })");
-  shouldThrow("context.addHitRegion({ id : null })");
   shouldThrow("context.addHitRegion({ id : undefined })");
   shouldThrow("context.addHitRegion({ control : {} })");
   shouldThrow("context.addHitRegion({ control : null })");
   shouldThrow("context.addHitRegion({ control : undefined })");
   shouldThrow("context.addHitRegion({ id : '', control : {} })");
-  shouldThrow("context.addHitRegion({ id : null, control : {} })");
   shouldThrow("context.addHitRegion({ id : undefined, control : {} })");
   shouldThrow("context.addHitRegion({ id : '', control : null })");
-  shouldThrow("context.addHitRegion({ id : null, control : null })");
   shouldThrow("context.addHitRegion({ id : undefined, control : null })");
   shouldThrow("context.addHitRegion({ id : '', control : undefined })");
-  shouldThrow("context.addHitRegion({ id : null, control : undefined })");
   shouldThrow("context.addHitRegion({ id : undefined, control : undefined })");
   debug("");