Workaround crash in WebContentsNSViewBridge::SetParentNSView

It has been observed that we are hitting the CHECK(parent_ns_view) in
WebContentsNSViewBridge::SetParentNSView.

Partially revert r625255, the culprit patch, by moving the functionality
of WebContentsNSViewBridge::SetParentNSView in to the caller,
NativeViewHostMac::AttachNativeView.

This is not a reasonable long-term solution, but is the most reasonable
merge candidate. Follow-on patches will move the CHECK up into
NativeViewHostMac::AttachNativeView to see exactly why this is
happening.

Bug: 933679
Change-Id: I08b19f3123bbe96c49376a41f28a879a855bee62
Reviewed-on: https://chromium-review.googlesource.com/c/1487888
Commit-Queue: ccameron <ccameron@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#635705}

content/browser/web_contents/web_contents_view_mac.mm

@@ -555,7 +555,12 @@
   } else if (factory_host_id != NSViewBridgeFactoryHost::kLocalDirectHostId) {
     LOG(ERROR) << "Failed to look up NSViewBridgeFactoryHost!";
   }
-  ns_view_bridge_local_->SetParentNSView(views_host_->GetNSViewId(), token);
+
+  // TODO(https://crbug.com/933679): WebContentsNSViewBridge::SetParentView
+  // will look up the parent NSView by its id, but this has been observed to
+  // fail in the field, so assume that the caller handles updating the NSView
+  // hierarchy.
+  // ns_view_bridge_local_->SetParentNSView(views_host_->GetNSViewId(), token);
 
   for (auto* rwhv_mac : GetChildViews()) {
     rwhv_mac->MigrateNSViewBridge(factory_host, ns_view_id_);

ui/views/controls/native/native_view_host_mac.mm

@@ -122,15 +122,17 @@ void EnsureNativeViewHasNoChildWidgets(NSView* native_view) {
   EnsureNativeViewHasNoChildWidgets(native_view_);
 
   auto* bridge_host = GetBridgedNativeWidgetHost();
-  DCHECK(bridge_host);
+  CHECK(bridge_host);
 
-  if (native_view_hostable_) {
+  // TODO(https://crbug.com/933679): This is lifted out the ViewsHostableAttach
+  // call below because of crashes being observed in the field.
+  NSView* superview =
+      bridge_host->native_widget_mac()->GetNativeView().GetNativeNSView();
+  [superview addSubview:native_view_];
+
+  if (native_view_hostable_)
     native_view_hostable_->ViewsHostableAttach(this);
-  } else {
-    NSView* superview =
-        bridge_host->native_widget_mac()->GetNativeView().GetNativeNSView();
-    [superview addSubview:native_view_];
-  }
+
   bridge_host->SetAssociationForView(host_, native_view_);
 }