aura: Fix unit_tests on linux

ui/aura/desktop_host_linux.cc

 // Copyright (c) 2011 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/desktop_host.h"
 
 #include <X11/cursorfont.h>
 #include <X11/Xlib.h>
 
 // Get rid of a macro from Xlib.h that conflicts with Aura's RootWindow class.
@@ skipping 204 matching lines @@
     case ui::VKEY_OEM_PLUS:
     case ui::VKEY_OEM_COMMA:
     case ui::VKEY_OEM_MINUS:
     case ui::VKEY_OEM_PERIOD:
       return true;
     default:
       return false;
   }
 }
 
-class DesktopHostLinux : public DesktopHost {
+class DesktopHostLinux : public DesktopHost,
+                         public MessageLoop::DestructionObserver {
  public:
   explicit DesktopHostLinux(const gfx::Rect& bounds);
   virtual ~DesktopHostLinux();
 
  private:
-  // base::MessageLoop::Dispatcher Override.
+  // MessageLoop::Dispatcher Override.
   virtual DispatchStatus Dispatch(XEvent* xev) OVERRIDE;
 
   // DesktopHost Overrides.
   virtual void SetDesktop(Desktop* desktop) OVERRIDE;
   virtual gfx::AcceleratedWidget GetAcceleratedWidget() OVERRIDE;
   virtual void Show() OVERRIDE;
   virtual void ToggleFullScreen() OVERRIDE;
   virtual gfx::Size GetSize() const OVERRIDE;
   virtual void SetSize(const gfx::Size& size) OVERRIDE;
   virtual gfx::Point GetLocationOnNativeScreen() const OVERRIDE;
   virtual void SetCursor(gfx::NativeCursor cursor_type) OVERRIDE;
   virtual gfx::Point QueryMouseLocation() OVERRIDE;
   virtual void PostNativeEvent(const base::NativeEvent& event) OVERRIDE;
 
+  // MessageLoop::DestructionObserver Overrides.
+  virtual void WillDestroyCurrentMessageLoop() OVERRIDE;
+
   // Returns true if there's an X window manager present... in most cases.  Some
   // window managers (notably, ion3) don't implement enough of ICCCM for us to
   // detect that they're there.
   bool IsWindowManagerPresent();
 
   Desktop* desktop_;
 
   // The display and the native X window hosting the desktop.
   Display* xdisplay_;
   ::Window xwindow_;
@@ skipping 29 matching lines @@
                     PointerMotionMask;
   XSelectInput(xdisplay_, xwindow_, event_mask);
   XSelectInput(xdisplay_, root_window_, StructureNotifyMask);
   XFlush(xdisplay_);
 
   // TODO(sadrul): reenable once 103981 is fixed.
 #if defined(TOUCH_UI)
   if (base::MessagePumpForUI::HasXInput2())
     ui::TouchFactory::GetInstance()->SetupXI2ForXWindow(xwindow_);
 #endif
+
+  base::MessagePumpX::SetDefaultDispatcher(this);
+  MessageLoopForUI::current()->AddDestructionObserver(this);
 }
 
 DesktopHostLinux::~DesktopHostLinux() {
   XDestroyWindow(xdisplay_, xwindow_);
 
   // Clears XCursorCache.
   ui::GetXCursor(ui::kCursorClearXCursorCache);
+
+  MessageLoopForUI::current()->RemoveDestructionObserver(this);
+  base::MessagePumpX::SetDefaultDispatcher(NULL);
 }
 
 base::MessagePumpDispatcher::DispatchStatus DesktopHostLinux::Dispatch(
     XEvent* xev) {
   DLOG(WARNING) << "DispatchEvent:" << xev->type;
 
   bool handled = false;
   switch (xev->type) {
     case Expose:
       desktop_->Draw();
@@ skipping 215 matching lines @@
       xevent.xmotion.x_root = point.x();
       xevent.xmotion.y_root = point.y();
     }
     default:
       break;
   }
   Status status = XSendEvent(xdisplay_, xwindow_, False, 0, &xevent);
   DLOG(WARNING) << "PostEvent:" << xevent.type << ", status=" << status;
 }
 
+void DesktopHostLinux::WillDestroyCurrentMessageLoop() {
+  desktop_->DeleteInstance();
+}
+
 bool DesktopHostLinux::IsWindowManagerPresent() {
   // Per ICCCM 2.8, "Manager Selections", window managers should take ownership
   // of WM_Sn selections (where n is a screen number).
   ::Atom wm_s0_atom = XInternAtom(xdisplay_, "WM_S0", False);
   return XGetSelectionOwner(xdisplay_, wm_s0_atom) != None;
 }
 
 }  // namespace
 
 // static
 DesktopHost* DesktopHost::Create(const gfx::Rect& bounds) {
   return new DesktopHostLinux(bounds);
 }
 
 // static
 gfx::Size DesktopHost::GetNativeScreenSize() {
   ::Display* xdisplay = base::MessagePumpX::GetDefaultXDisplay();
   return gfx::Size(DisplayWidth(xdisplay, 0), DisplayHeight(xdisplay, 0));
 }
 
 }  // namespace aura