Use testharness.js instead of js-test.js in OffscreenCanvas tests.

third_party/WebKit/LayoutTests/fast/canvas/OffscreenCanvas-invalid-args-expected.txt

Index: third_party/WebKit/LayoutTests/fast/canvas/OffscreenCanvas-invalid-args-expected.txt
diff --git a/third_party/WebKit/LayoutTests/fast/canvas/OffscreenCanvas-invalid-args-expected.txt b/third_party/WebKit/LayoutTests/fast/canvas/OffscreenCanvas-invalid-args-expected.txt
deleted file mode 100644
index 9f86eece295254b19500ab87d43c6dae3e58350f..0000000000000000000000000000000000000000
--- a/third_party/WebKit/LayoutTests/fast/canvas/OffscreenCanvas-invalid-args-expected.txt
+++ /dev/null
@@ -1,23 +0,0 @@
-Tests that the OffscreenCanvas can handle invalid arguments
-
-On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
-
-
-PASS canvas1.width is setWidth-1
-PASS canvas1.height is setHeight-1
-PASS canvas1.width is 0
-PASS canvas1.height is 0
-PASS new OffscreenCanvas(-1, -1) threw exception TypeError: Failed to construct 'OffscreenCanvas': Value is outside the 'unsigned long' value range..
-PASS canvas2.width is 0
-PASS canvas2.height is 0
-PASS canvas2.width is setWidth-1
-PASS canvas2.height is setHeight-1
-PASS canvas2.width = -1 threw exception TypeError: Failed to set the 'width' property on 'OffscreenCanvas': Value is outside the 'unsigned long' value range..
-PASS canvas2.height = -1 threw exception TypeError: Failed to set the 'height' property on 'OffscreenCanvas': Value is outside the 'unsigned long' value range..
-PASS canvas2.width = obj threw exception TypeError: Failed to set the 'width' property on 'OffscreenCanvas': Value is not of type 'unsigned long'..
-PASS canvas2.height = obj threw exception TypeError: Failed to set the 'height' property on 'OffscreenCanvas': Value is not of type 'unsigned long'..
-PASS new OffscreenCanvas(obj, obj) threw exception TypeError: Failed to construct 'OffscreenCanvas': Value is not of type 'unsigned long'..
-PASS successfullyParsed is true
-
-TEST COMPLETE
-