Emit console warning when element.animate() keyframe value fails to parse

third_party/WebKit/LayoutTests/animations/element-animate-keyframe-value-warning.html

Index: third_party/WebKit/LayoutTests/animations/element-animate-keyframe-value-warning.html
diff --git a/third_party/WebKit/LayoutTests/animations/element-animate-keyframe-value-warning.html b/third_party/WebKit/LayoutTests/animations/element-animate-keyframe-value-warning.html
new file mode 100644
index 0000000000000000000000000000000000000000..d760c84af8acd1ce728c77f4ae7207ed2dea4757
--- /dev/null
+++ b/third_party/WebKit/LayoutTests/animations/element-animate-keyframe-value-warning.html
@@ -0,0 +1,12 @@
+<div id="target"></div>
+This test passes if there are three warninga about invalid keyframe values.

[Timothy Loh, 2016/11/24 23:00:23]

warninga -> warnings

+<script>
+if (window.testRunner) {
+  testRunner.dumpAsText();
+}
+target.animate({offsetPath: 'path("m0 0")'});
+target.animate({offsetPath: 'path("invalid")'});
+target.animate({'--x': 'valid'});
+target.animate({'--x': 'invalid )'});
+target.animate({'--x': 'invalid !important'});
+</script>