Fix DesktopWindowTreeHostX11Test.Shape on Unity

ui/views/widget/desktop_aura/desktop_window_tree_host_x11_unittest.cc

Index: ui/views/widget/desktop_aura/desktop_window_tree_host_x11_unittest.cc
diff --git a/ui/views/widget/desktop_aura/desktop_window_tree_host_x11_unittest.cc b/ui/views/widget/desktop_aura/desktop_window_tree_host_x11_unittest.cc
index 2e1f5dbf3a1b1de25e7fec7b39d132371d205423..eac324b69b19e15c0ff05b4da845251f76ff1986 100644
--- a/ui/views/widget/desktop_aura/desktop_window_tree_host_x11_unittest.cc
+++ b/ui/views/widget/desktop_aura/desktop_window_tree_host_x11_unittest.cc
@@ -12,6 +12,7 @@
 #undef None
 
 #include "base/memory/scoped_ptr.h"
+#include "base/run_loop.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_tree_host.h"
 #include "ui/base/hit_test.h"
@@ -189,6 +190,12 @@ bool ShapeRectContainsPoint(const std::vector<gfx::Rect>& shape_rects,
   return false;
 }
 
+// Flush the message loop.
+void RunAllPendingInMessageLoop() {
+  base::RunLoop run_loop;
+  run_loop.RunUntilIdle();
+}
+
 }  // namespace
 
 class DesktopWindowTreeHostX11Test : public ViewsTestBase {
@@ -263,6 +270,9 @@ TEST_F(DesktopWindowTreeHostX11Test, Shape) {
       waiter.Wait();
     }
 
+    // Ensure that the task which is posted when a window is resized is run.
+    RunAllPendingInMessageLoop();
+
     // xvfb does not support Xrandr so we cannot check the maximized window's
     // bounds.
     gfx::Rect maximized_bounds;