Make ScopedWindowTargeter add itself as a WindowObserver for real

ui/aura/window_targeter_unittest.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/aura/window_targeter.h"
 
 #include "ui/aura/scoped_window_targeter.h"
 #include "ui/aura/test/aura_test_base.h"
 #include "ui/aura/test/test_window_delegate.h"
 #include "ui/aura/window.h"
@@ skipping 100 matching lines @@
     EXPECT_EQ(window.get(), targeter->FindTargetForEvent(root, &mouse));
   }
   scoped_targeter.reset();
   {
     ui::MouseEvent mouse(ui::ET_MOUSE_MOVED, event_location, event_location,
                          ui::EF_NONE, ui::EF_NONE);
     EXPECT_EQ(child, targeter->FindTargetForEvent(root, &mouse));
   }
 }
 
+// Test that ScopedWindowTargeter does not crash if the window for which it
+// replaces the targeter gets destroyed before it does.
+TEST_F(WindowTargeterTest, ScopedWindowTargeterWindowDestroyed) {
+  test::TestWindowDelegate delegate;
+  scoped_ptr<Window> window(CreateNormalWindow(1, root_window(), &delegate));
+  scoped_ptr<ScopedWindowTargeter> scoped_targeter(
+      new ScopedWindowTargeter(window.get(), scoped_ptr<ui::EventTargeter>(
+          new StaticWindowTargeter(window.get()))));
+
+  window.reset();
+  scoped_targeter.reset();
+
+  // We did not crash!
+}
+
 TEST_F(WindowTargeterTest, TargetTransformedWindow) {
   root_window()->Show();
 
   test::TestWindowDelegate delegate;
   scoped_ptr<Window> window(CreateNormalWindow(2, root_window(), &delegate));
 
   const gfx::Rect window_bounds(100, 20, 400, 80);
   window->SetBounds(window_bounds);
 
   ui::EventTarget* root_target = root_window();
@@ skipping 25 matching lines @@
   EXPECT_EQ(gfx::RectF(300, 30, 200, 40).ToString(),
             GetEffectiveVisibleBoundsInRootWindow(window.get()).ToString());
   {
     ui::MouseEvent mouse(ui::ET_MOUSE_MOVED, event_location, event_location,
                          ui::EF_NONE, ui::EF_NONE);
     EXPECT_EQ(window.get(), targeter->FindTargetForEvent(root_target, &mouse));
   }
 }
 
 }  // namespace aura