Keep a copy of affected players while notifying abrupt rendering stop.

https://bugs.webkit.org/show_bug.cgi?id=291973
rdar://149869888

Reviewed by Ada Chan.

Calling renderingAbruptlyStopped() may lead to a ModelPlayer creation
when model's auto-reload logic kicks in. Consecutively that leads to
m_players being changed while iterating over the HashMap.
Having a copy of currently affected players helps to mitigate that.

* Source/WebKit/WebProcess/Model/ModelProcessModelPlayerManager.cpp:
(WebKit::ModelProcessModelPlayerManager::modelProcessConnectionDidClose):

Canonical link: https://commits.webkit.org/294071@main

Author: amarchenko

Source/WebKit/WebProcess/Model/ModelProcessModelPlayerManager.cpp

@@ -91,7 +91,8 @@ void ModelProcessModelPlayerManager::modelProcessConnectionDidClose(ModelProcess
 {
     m_modelProcessConnection = nullptr;
 
-    for (auto& entry : m_players) {
+    auto playersToNotify = m_players;
+    for (auto& entry : playersToNotify) {
         if (RefPtr player = entry.value.get())
             player->renderingAbruptlyStopped();
     }