Import Cobalt 19.master.0.203780

Includes the following patches:
  https://cobalt-review.googlesource.com/c/cobalt/+/5210
    by errong.leng@samsung.com
  https://cobalt-review.googlesource.com/c/cobalt/+/5270
    by linus.wang@samsung.com
diff --git a/src/third_party/web_platform_tests/webgl/common.js b/src/third_party/web_platform_tests/webgl/common.js
new file mode 100644
index 0000000..416c21c
--- /dev/null
+++ b/src/third_party/web_platform_tests/webgl/common.js
@@ -0,0 +1,13 @@
+function getGl() {
+  var c = document.createElement("canvas");
+  var gl = c.getContext("experimental-webgl");
+  assert_true(!!gl, "Should be able to get a context.");
+  return gl;
+}
+
+function shouldGenerateGLError(cx, glError, fn) {
+  test(function() {
+    fn();
+    assert_equals(cx.getError(), glError);
+  }, "Calling " + fn + " should generate a " + glError + " error.");
+}