Add null check to fill, stroke, clip method

LayoutTests/fast/canvas/script-tests/canvas-path-context-fill.js

Index: LayoutTests/fast/canvas/script-tests/canvas-path-context-fill.js
diff --git a/LayoutTests/fast/canvas/script-tests/canvas-path-context-fill.js b/LayoutTests/fast/canvas/script-tests/canvas-path-context-fill.js
index c394d6b92c290be67cf7d39a30e597afb9650778..9d7a9bb54cbaab9ce088d93993fb62b609a0dd30 100644
--- a/LayoutTests/fast/canvas/script-tests/canvas-path-context-fill.js
+++ b/LayoutTests/fast/canvas/script-tests/canvas-path-context-fill.js
@@ -64,6 +64,12 @@ function prepareTestScenario() {
     // Test exception cases.
     shouldThrow("ctx.fill(null)");
     shouldThrow("ctx.fill(null, null)");
+    shouldThrow("ctx.fill(null, 'nonzero')");
+    shouldThrow("ctx.fill([], 'nonzero')");
+    shouldThrow("ctx.fill({}, 'nonzero')");
+    shouldThrow("ctx.fill(null, 'evenodd')");
+    shouldThrow("ctx.fill([], 'evenodd')");
+    shouldThrow("ctx.fill({}, 'evenodd')");
 }
 
 // Run test and allow variation of results.