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26 December 2018, 22:31:15 UTC
Revision 4e5f09f89e6f1976dd49a57ba46cd447c7e19a1e authored by Alex Moshchuk on 13 April 2018, 15:22:14 UTC, committed by Chromium WPT Sync on 13 April 2018, 15:22:14 UTC 
Reland: Use PostTask to schedule cross-process postMessage forwarding.
 
Changes from original attempt at https://crrev.com/c/999182:
- fix flakiness in two additional ChromeOS login tests
- fix CSP WPT tests to not depend on ordering between iframe's onload
  and postMessage - see https://crbug.com/832319.

Previously, we sent the IPC to forward a cross-process postMessage
immediately.  This caused a behavioral difference from the
same-process case where the postMessage is always scheduled.  Namely,
in a scenario like this:

  frame.postMessage(...);
  doSomethingThatSendsIPCsToFrame(frame);

the IPCs from JS following the postMessage would've been ordered
incorrectly, causing |frame| to see their side effects after the
postMessage dispatch in the cross-process case, whereas they would be
seen before the postMessage dispatch in the same-process case.  One
example of this is frame.focus(), and another is a frame element
onload event (dispatched via FrameHostMsg_DispatchLoad) arriving after
a postMessage dispatched from an inline script while the frame was
still loading.

To resolve these ordering concerns, this CL changes cross-process
postMessage to do a PostTask on the sender side before sending the
message to the browser process.  This improves the current state of
the world, but does not yet achieve a perfect match for the IPC
ordering in the same-process case - see discussion on the bug.

Bug: 828529
Change-Id: I62a627c501526d09900be4f5bd2c899acf4d1e07
Reviewed-on: https://chromium-review.googlesource.com/999182
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Commit-Queue: Alex Moshchuk <alexmos@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#550284}
Reviewed-on: https://chromium-review.googlesource.com/1011287
Cr-Commit-Position: refs/heads/master@{#550621}
1 parent f90d3d6
Raw File
Tip revision: 4e5f09f89e6f1976dd49a57ba46cd447c7e19a1e authored by Alex Moshchuk on 13 April 2018, 15:22:14 UTC
Reland: Use PostTask to schedule cross-process postMessage forwarding.
Tip revision: 4e5f09f
zero-area-element-visible.html 
<!DOCTYPE html>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="./resources/intersection-observer-test-utils.js"></script>

<style>
pre, #log {
  position: absolute;
  top: 0;
  left: 200px;
}
#target {
  width: 0px;
  height: 0px;
}
</style>

<div id='target'></div>

<script>
var entries = [];

runTestCycle(function() {
  var target = document.getElementById('target');
  assert_true(!!target, "target exists");
  var observer = new IntersectionObserver(function(changes) {
    entries = entries.concat(changes)
  });
  observer.observe(target);
  entries = entries.concat(observer.takeRecords());
  assert_equals(entries.length, 0, "No initial notifications.");
  runTestCycle(step0, "First rAF should generate a notification.");
}, "Ensure that a zero-area target intersecting root generates a notification with intersectionRatio == 1");

function step0() {
  assert_equals(entries.length, 1, "One notification.");
  assert_equals(entries[0].intersectionRatio, 1, "intersectionRatio == 1");
}
</script>
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