Revert "[DL]: Ensure to reject update/commit promises on disconnected elements."

This reverts commit 5f4ce97e.

Reason for revert: On https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/Linux%20Tests%20%28dbg%29%281%29?limit=200, virtual/display-lock/display-lock/lock-before-append/acquire-update-measure-remove.html has been failing about 90% of the time since this landed.

Original change's description:
> [DL]: Ensure to reject update/commit promises on disconnected elements.
> 
> This patch ensures that we reject update/commit when it happens on
> a disconnected element.
> 
> R=​chrishtr@chromium.org
> 
> Bug: 882663
> Change-Id: Iaee923a4f41714b437c0a2b85bbb175359a2f32c
> Reviewed-on: https://chromium-review.googlesource.com/c/1387944
> Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
> Commit-Queue: Chris Harrelson <chrishtr@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#618713}

TBR=vmpstr@chromium.org,chrishtr@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 882663
Change-Id: I491a3f7db511a69f2538e3158bc4666c6f9eaf85
Reviewed-on: https://chromium-review.googlesource.com/c/1390433Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Avi Drissman <avi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#618847}

third_party/blink/renderer/core/display_lock/display_lock_context.cc

@@ -139,8 +139,8 @@ ScriptPromise DisplayLockContext::acquire(ScriptState* script_state,
 }
 
 ScriptPromise DisplayLockContext::update(ScriptState* script_state) {
-  // Reject if we're unlocked or disconnected.
-  if (state_ == kUnlocked || !element_->isConnected())
+  // Reject if we're unlocked.
+  if (state_ == kUnlocked)
     return GetRejectedPromise(script_state);
 
   // If we have a resolver, then we're at least updating already, just return
@@ -151,13 +151,16 @@ ScriptPromise DisplayLockContext::update(ScriptState* script_state) {
   }
 
   update_resolver_ = ScriptPromiseResolver::Create(script_state);
-  StartUpdateIfNeeded();
+  // We only need to kick off an Update if we're in a locked state, all other
+  // states are already updating.
+  if (state_ == kLocked)
+    StartUpdate();
   return update_resolver_->Promise();
 }
 
 ScriptPromise DisplayLockContext::commit(ScriptState* script_state) {
-  // Reject if we're unlocked or disonnected.
-  if (state_ == kUnlocked || !element_->isConnected())
+  // Reject if we're unlocked.
+  if (state_ == kUnlocked)
     return GetRejectedPromise(script_state);
 
   // If we have a resolver, we must be committing already, just return the same
@@ -388,19 +391,12 @@ void DisplayLockContext::StartCommit() {
       layout_invalidation_reason::kDisplayLockCommitting);
 }
 
-void DisplayLockContext::StartUpdateIfNeeded() {
-  // We should not be calling this if we're unlocked.
-  DCHECK_NE(state_, kUnlocked);
-  // Any state other than kLocked means that we are already in the process of
-  // updating/committing, so we can piggy back on that process without kicking
-  // off any new updates.
-  if (state_ != kLocked)
-    return;
-
+void DisplayLockContext::StartUpdate() {
+  DCHECK_EQ(state_, kLocked);
+  state_ = kUpdating;
   // We don't need to mark anything dirty since the budget will take care of
   // that for us.
   update_budget_ = CreateNewBudget();
-  state_ = kUpdating;
   ScheduleAnimation();
 }
 
@@ -513,8 +509,6 @@ void DisplayLockContext::DidFinishLifecycleUpdate() {
 }
 
 void DisplayLockContext::ScheduleAnimation() {
-  DCHECK(element_->isConnected());
-
   // Schedule an animation to perform the lifecycle phases.
   element_->GetDocument().GetPage()->Animator().ScheduleVisualUpdate(
       element_->GetDocument().GetFrame());

third_party/blink/renderer/core/display_lock/display_lock_context.h

@@ -149,7 +149,7 @@ class CORE_EXPORT DisplayLockContext final
   // Initiate a commit.
   void StartCommit();
   // Initiate an update.
-  void StartUpdateIfNeeded();
+  void StartUpdate();
 
   // The following functions propagate dirty bits from the locked element up to
   // the ancestors in order to be reached. They return true if the element or

third_party/blink/web_tests/display-lock/lock-before-append/commit-while-disconnected-expected.html

-<!doctype HTML>
-
-<div id="log">PASS</div>
-

third_party/blink/web_tests/display-lock/lock-before-append/commit-while-disconnected.html

-<!doctype HTML>
-
-<!--
-Runs an acquire(), then commits without connecting the element.
--->
-
-<div id="log"></div>
-
-<script>
-// TODO(vmpstr): In WPT this needs to be replaced with reftest-wait.
-if (window.testRunner)
-  window.testRunner.waitUntilDone();
-
-function finishTest(status_string) {
-  if (document.getElementById("log").innerHTML === "")
-    document.getElementById("log").innerHTML = status_string;
-  if (window.testRunner)
-    window.testRunner.notifyDone();
-}
-
-function runTest() {
-  let container = document.createElement("div");
-  container.id = "container";
-
-  container.getDisplayLock().acquire({ timeout: Infinity }).then(() => {
-    container.getDisplayLock().commit().then(
-      () => { finishTest("FAIL"); },
-      () => { finishTest("PASS"); });
-  });
-}
-
-window.onload = runTest;
-</script>

third_party/blink/web_tests/display-lock/lock-before-append/update-while-disconnected-expected.html

-<!doctype HTML>
-
-<div id="log">PASS</div>
-

third_party/blink/web_tests/display-lock/lock-before-append/update-while-disconnected.html

-<!doctype HTML>
-
-<!--
-Runs an acquire(), then updates without connecting the element.
--->
-
-<div id="log"></div>
-
-<script>
-// TODO(vmpstr): In WPT this needs to be replaced with reftest-wait.
-if (window.testRunner)
-  window.testRunner.waitUntilDone();
-
-function finishTest(status_string) {
-  if (document.getElementById("log").innerHTML === "")
-    document.getElementById("log").innerHTML = status_string;
-  if (window.testRunner)
-    window.testRunner.notifyDone();
-}
-
-function runTest() {
-  let container = document.createElement("div");
-  container.id = "container";
-
-  container.getDisplayLock().acquire({ timeout: Infinity }).then(() => {
-    container.getDisplayLock().update().then(
-      () => { finishTest("FAIL"); },
-      () => { finishTest("PASS"); });
-  });
-}
-
-window.onload = runTest;
-</script>