Speculative fix for crasher

The presumptive scenario is remote iframe inside a throttled iframe
inside an active top document. The top document runs a lifecycle
update, which succeeds (i.e., the return value from
LocalFrameView::UpdateAllLifecyclePhases is 'true'); but the middle
frame is throttled and doesn't update, so we can't do a hit test on
it. In that case, just give up on trying to compute occlusion
information.

BUG=1041252
R=chrishtr@chromium.org

Change-Id: If7fadc9daf033bceda9f8a01edc6c3cabf71c066
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2003259Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Commit-Queue: Stefan Zager <szager@chromium.org>
Cr-Commit-Position: refs/heads/master@{#732489}

third_party/blink/renderer/core/frame/remote_frame.cc

@@ -388,11 +388,11 @@ void RemoteFrame::UpdateHitTestOcclusionData() {
   bool unoccluded = false;
   if (base::FeatureList::IsEnabled(
           blink::features::kVizHitTestOcclusionCheck)) {
-    if (HTMLFrameOwnerElement* owner_element = DeprecatedLocalOwner()) {
-      if (LayoutObject* owner = owner_element->GetLayoutObject()) {
+    if (LayoutEmbeddedContent* owner = OwnerLayoutObject()) {
+      if (!owner->GetFrameView()->CanThrottleRendering()) {
         HitTestResult hit_test_result(owner->HitTestForOcclusion());
         const Node* hit_node = hit_test_result.InnerNode();
-        unoccluded = (!hit_node || hit_node == owner_element);
+        unoccluded = (!hit_node || hit_node == owner->GetNode());
       }
     }
   }