NULL-check before accessing toplevel_window_ to avoid race-condition crash.

To reliably reproduce (before this patch), run browser_tests
--gtest_filter=ExtensionApiTest.ShowPageActionPopup and then move the
mouse pointer outside of the browser window.

BUG=none
TEST=fixes ExtensionApiTest.ShowPageActionPopup

Review URL: http://codereview.chromium.org/1555006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@43612 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 12 insertions, 1 deletions

diff --git a/chrome/browser/gtk/info_bubble_gtk.cc b/chrome/browser/gtk/info_bubble_gtk.cc
index beae5d4..abbaf5c 100644
--- a/chrome/browser/gtk/info_bubble_gtk.cc
+++ b/chrome/browser/gtk/info_bubble_gtk.cc
@@ -110,6 +110,7 @@ void InfoBubbleGtk::Init(GtkWindow* toplevel_window,
 
   DCHECK(!window_);
   toplevel_window_ = toplevel_window;
+  DCHECK(toplevel_window_);
   rect_ = rect;
   preferred_arrow_location_ = arrow_location;
 
@@ -258,6 +259,9 @@ InfoBubbleGtk::ArrowLocationGtk InfoBubbleGtk::GetArrowLocation(
 }
 
 bool InfoBubbleGtk::UpdateArrowLocation(bool force_move_and_reshape) {
+  if (!toplevel_window_)
+    return false;
+
   gint toplevel_x = 0, toplevel_y = 0;
   gdk_window_get_position(
       GTK_WIDGET(toplevel_window_)->window, &toplevel_x, &toplevel_y);
@@ -294,6 +298,9 @@ void InfoBubbleGtk::UpdateWindowShape() {
 }
 
 void InfoBubbleGtk::MoveWindow() {
+  if (!toplevel_window_)
+    return;
+
   gint toplevel_x = 0, toplevel_y = 0;
   gdk_window_get_position(
       GTK_WIDGET(toplevel_window_)->window, &toplevel_x, &toplevel_y);
@@ -316,7 +323,8 @@ void InfoBubbleGtk::MoveWindow() {
 
 void InfoBubbleGtk::StackWindow() {
   // Stack our window directly above the toplevel window.
-  gtk_util::StackPopupWindow(window_, GTK_WIDGET(toplevel_window_));
+  if (toplevel_window_)
+    gtk_util::StackPopupWindow(window_, GTK_WIDGET(toplevel_window_));
 }
 
 void InfoBubbleGtk::Observe(NotificationType type,
diff --git a/chrome/browser/gtk/info_bubble_gtk.h b/chrome/browser/gtk/info_bubble_gtk.h
index 10274fa..e5601fd 100644
--- a/chrome/browser/gtk/info_bubble_gtk.h
+++ b/chrome/browser/gtk/info_bubble_gtk.h
@@ -172,6 +172,9 @@ class InfoBubbleGtk : public NotificationObserver {
   GtkAccelGroup* accel_group_;
 
   // The window for which we're being shown (and to which |rect_| is relative).
+  // Note that it's possible for |toplevel_window_| to be NULL if the
+  // window is destroyed before this object is destroyed, so it's important
+  // to check for that case.
   GtkWindow* toplevel_window_;
 
   // Provides an offset from |toplevel_window_|'s origin for MoveWindow() to