aura: Destroy the compositor before destroying the backing window.

ui/gfx/win/window_impl.cc

Index: ui/gfx/win/window_impl.cc
diff --git a/ui/gfx/win/window_impl.cc b/ui/gfx/win/window_impl.cc
index 3ca3f900102feb7beb0788c1a5e0d4fbb65b1ee1..a8e10b09c01f5f6c18f9742dbbaf633269fdd009 100644
--- a/ui/gfx/win/window_impl.cc
+++ b/ui/gfx/win/window_impl.cc
@@ -219,6 +219,11 @@ void WindowImpl::Init(HWND parent, const Rect& bounds) {
   CHECK_EQ(this, GetWindowUserData(hwnd));
 }
 
+void WindowImpl::Destroy() {

[Ben Goodger (Google), 2014/01/14 21:48:03]

you actually can't rely on people calling this function.

for example, Windows might destroy your window, and just send you a WM_DESTROY
to let you know it did.

WM_DESTROY - "Windows is destroying your window, and the HWND is still valid. Do
some cleanup that needs the HWND to be alive. There is no way out."
WM_NCDESTROY - "Windows destroyed your window. The HWND is now bogus. Goodbye."

+  DestroyWindow(hwnd());
+  hwnd_ = NULL;

[Ben Goodger (Google), 2014/01/14 21:48:03]

... and so this should be set in a handler for WM_NCDESTROY in WndProc below.

[danakj, 2014/01/14 21:58:41]

Oh I see. The handler for WM_NCDESTROY appears to be in hwnd_message_handler.cc,
so from there I called SetDestroyed(), a method on this class that sets hwnd_ =
NULL. Then I DCHECK that the hwnd is NULL out in the
DesktopWindowTreeHostWin::HandleDestroyed.

+}
+
 HICON WindowImpl::GetDefaultWindowIcon() const {
   return NULL;
 }