Check for destroyed window observers which haven't stopped observing windows.

This is a temporary patch to catch the cause of a crashing bug and should be reverted when the bug is fixed.

BUG=177012
TEST=trybots


Review URL: https://chromiumcodereview.appspot.com/12320021

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@185719 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 8 insertions, 2 deletions

diff --git a/ash/wm/frame_painter_unittest.cc b/ash/wm/frame_painter_unittest.cc
index 4fab97b..72754b9 100644
--- a/ash/wm/frame_painter_unittest.cc
+++ b/ash/wm/frame_painter_unittest.cc
@@ -69,10 +69,13 @@ class ResizableWidgetDelegate : public views::WidgetDelegate {
 class WindowRepaintChecker : public aura::WindowObserver {
  public:
   explicit WindowRepaintChecker(aura::Window* window)
-      : is_paint_scheduled_(false) {
-    window->AddObserver(this);
+      : window_(window),
+        is_paint_scheduled_(false) {
+    window_->AddObserver(this);
   }
   virtual ~WindowRepaintChecker() {
+    if (window_)
+      window_->RemoveObserver(this);
   }
 
   bool IsPaintScheduledAndReset() {
@@ -88,9 +91,12 @@ class WindowRepaintChecker : public aura::WindowObserver {
     is_paint_scheduled_ = true;
   }
   virtual void OnWindowDestroying(aura::Window* window) OVERRIDE {
+    DCHECK_EQ(window_, window);
+    window_ = NULL;
     window->RemoveObserver(this);
   }
 
+  aura::Window* window_;
   bool is_paint_scheduled_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowRepaintChecker);