Defer media loading while on cellular networks.

third_party/WebKit/LayoutTests/media/video-preload-cellular-test.js

+function CellularPreloadTest(preloadType) {

[philipj_slow, 2015/10/21 11:11:29]

LayoutTests/media/video-controls-fullscreen.js shows how you can move the
async_test bit into the shared JS. Although atypical, I would go with
cellular_preload_test() to match async_test() or cellularPreloadTest() if you
think that's lame :)

[DaleCurtis, 2015/10/21 22:34:32]

lowercase_for_the_win().

+  return function(t) {
+    internals.setNetworkStateNotifierTestOnly(true);
+    internals.setNetworkConnectionInfo('cellular', 2.0);
+
+    var video = document.createElement('video');
+    if (preloadType)
+      video.preload = preloadType;

[philipj_slow, 2015/10/21 11:11:29]

After this line, can you also assert_equals(video.preload, "none")? Otherwise we
could do the coercing entirely internally without failing this test.

[DaleCurtis, 2015/10/21 22:34:32]

Done.

+    video.src = 'resources/test-positive-start-time.webm';
+
+    video.onsuspend = t.step_func_done();
+    video.onprogress = t.unreached_func();
+    t.add_cleanup(function() {
+      internals.setNetworkStateNotifierTestOnly(false);
+    });
+  }
+}