Merge r167883 - [GTK] Crash in debug build with removing windowed plu…

…gin child widgets from the view

https://bugs.webkit.org/show_bug.cgi?id=132252

Reviewed by Philippe Normand.

It crashes due to an assert in HashTable that checks the iterators
validity. The problem is that we are iterating the children map
and the callback called on every iteration might modify the map,
making the iterators invalid. This happens when the WebView is
destroyed, GtkContainer calls gtk_container_foreach() with
gtk_widget_destroy as callback. When a widget inside a container
is destroyed, it's removed from the container, and in our case,
the child widget is removed from the map. This fixes several
crashes when running layout tests in debug bot.

* UIProcess/API/gtk/WebKitWebViewBase.cpp:
(webkitWebViewBaseContainerForall): Use copyKeysToVector() instead
of using a range iterator for the map keys and check in every
iteration that the child widget from the keys vector is still
present in the map before calling the callback.

Source/WebKit2/ChangeLog

@@ -1,3 +1,26 @@
+2014-04-28  Carlos Garcia Campos  <cgarcia@igalia.com>
+
+        [GTK] Crash in debug build with removing windowed plugin child widgets from the view
+        https://bugs.webkit.org/show_bug.cgi?id=132252
+
+        Reviewed by Philippe Normand.
+
+        It crashes due to an assert in HashTable that checks the iterators
+        validity. The problem is that we are iterating the children map
+        and the callback called on every iteration might modify the map,
+        making the iterators invalid. This happens when the WebView is
+        destroyed, GtkContainer calls gtk_container_foreach() with
+        gtk_widget_destroy as callback. When a widget inside a container
+        is destroyed, it's removed from the container, and in our case,
+        the child widget is removed from the map. This fixes several
+        crashes when running layout tests in debug bot.
+
+        * UIProcess/API/gtk/WebKitWebViewBase.cpp:
+        (webkitWebViewBaseContainerForall): Use copyKeysToVector() instead
+        of using a range iterator for the map keys and check in every
+        iteration that the child widget from the keys vector is still
+        present in the map before calling the callback.
+
 2014-04-22  Carlos Garcia Campos  <cgarcia@igalia.com>
 
         [GTK] Crash after getting web view context property with g_object_get

Source/WebKit2/UIProcess/API/gtk/WebKitWebViewBase.cpp

@@ -362,8 +362,12 @@ static void webkitWebViewBaseContainerForall(GtkContainer* container, gboolean i
     WebKitWebViewBase* webView = WEBKIT_WEB_VIEW_BASE(container);
     WebKitWebViewBasePrivate* priv = webView->priv;
 
-    for (const auto& widget : priv->children.keys())
-        (*callback)(widget, callbackData);
+    Vector<GtkWidget*> children;
+    copyKeysToVector(priv->children, children);
+    for (const auto& child : children) {
+        if (priv->children.contains(child))
+            (*callback)(child, callbackData);
+    }
 
     if (includeInternals && priv->inspectorView)
         (*callback)(priv->inspectorView, callbackData);