3 files changed, 21 insertions, 8 deletions
diff --git a/chrome/browser/renderer_host/resource_message_filter_gtk.cc b/chrome/browser/renderer_host/resource_message_filter_gtk.cc
index 56b53fe..97e1c14 100644
--- a/chrome/browser/renderer_host/resource_message_filter_gtk.cc
+++ b/chrome/browser/renderer_host/resource_message_filter_gtk.cc
@@ -70,6 +70,7 @@ void ResourceMessageFilter::DoOnGetWindowRect(gfx::NativeViewId view,
   gfx::Rect rect;
   XID window;
 
+  AutoLock lock(Singleton<GtkNativeViewManager>()->unrealize_lock());
   if (Singleton<GtkNativeViewManager>()->GetXIDForId(&window, view)) {
     if (window) {
       int x, y;
@@ -109,13 +110,16 @@ void ResourceMessageFilter::DoOnGetRootWindowRect(gfx::NativeViewId view,
   gfx::Rect rect;
   XID window;
 
+  AutoLock lock(Singleton<GtkNativeViewManager>()->unrealize_lock());
   if (Singleton<GtkNativeViewManager>()->GetXIDForId(&window, view)) {
     if (window) {
       const XID toplevel = GetTopLevelWindow(window);
-      int x, y;
-      unsigned width, height;
-      if (x11_util::GetWindowGeometry(&x, &y, &width, &height, toplevel))
-        rect = gfx::Rect(x, y, width, height);
+      if (toplevel) {
+        int x, y;
+        unsigned width, height;
+        if (x11_util::GetWindowGeometry(&x, &y, &width, &height, toplevel))
+          rect = gfx::Rect(x, y, width, height);
+      }
     }
   }
 
diff --git a/gfx/gtk_native_view_id_manager.cc b/gfx/gtk_native_view_id_manager.cc
index 47dc2fb..91407283a 100644
--- a/gfx/gtk_native_view_id_manager.cc
+++ b/gfx/gtk_native_view_id_manager.cc
@@ -116,6 +116,7 @@ void GtkNativeViewManager::OnRealize(gfx::NativeView widget) {
 }
 
 void GtkNativeViewManager::OnUnrealize(gfx::NativeView widget) {
+  AutoLock unrealize_locked(unrealize_lock_);
   AutoLock locked(lock_);
 
   const gfx::NativeViewId id = GetWidgetId(widget);
diff --git a/gfx/gtk_native_view_id_manager.h b/gfx/gtk_native_view_id_manager.h
index 048cd2d..3a23942 100644
--- a/gfx/gtk_native_view_id_manager.h
+++ b/gfx/gtk_native_view_id_manager.h
@@ -63,6 +63,8 @@ class GtkNativeViewManager {
   void OnUnrealize(gfx::NativeView widget);
   void OnDestroy(gfx::NativeView widget);
 
+  Lock& unrealize_lock() { return unrealize_lock_; }
+
  private:
   // This object is a singleton:
   GtkNativeViewManager();
@@ -78,12 +80,18 @@ class GtkNativeViewManager {
 
   gfx::NativeViewId GetWidgetId(gfx::NativeView id);
 
+  // This lock can be used to block GTK from unrealizing windows. This is needed
+  // when the BACKGROUND_X11 thread is using a window obtained via GetXIDForId,
+  // and can't allow the X11 resource to be deleted.
+  Lock unrealize_lock_;
+
   // protects native_view_to_id_ and id_to_info_
   Lock lock_;
-    // If asked for an id for the same widget twice, we want to return the same
-    // id. So this records the current mapping.
-    std::map<gfx::NativeView, gfx::NativeViewId> native_view_to_id_;
-    std::map<gfx::NativeViewId, NativeViewInfo> id_to_info_;
+
+  // If asked for an id for the same widget twice, we want to return the same
+  // id. So this records the current mapping.
+  std::map<gfx::NativeView, gfx::NativeViewId> native_view_to_id_;
+  std::map<gfx::NativeViewId, NativeViewInfo> id_to_info_;
 
   DISALLOW_COPY_AND_ASSIGN(GtkNativeViewManager);
 };