Fixes to get view_manager_lib_unittests not crash

. ICU may be initialized twice: once by the test suite, secondly by
  the app.
. window_mamanger_app_.host_ may be deleted by the time we get to the
  destructor to try and remove something. Add check for this.

BUG=none
TEST=none
R=viettrungluu@chromium.org

Review URL: https://codereview.chromium.org/516523004

Cr-Commit-Position: refs/heads/master@{#292929}

mojo/examples/window_manager/window_manager.cc

@@ -265,7 +265,10 @@ class WindowManager
         app_(NULL) {}
 
   virtual ~WindowManager() {
-    window_manager_app_->host()->window()->RemovePreTargetHandler(this);
+    // host() may be destroyed by the time we get here.
+    // TODO: figure out a way to always cleanly remove handler.
+    if (window_manager_app_->host())
+      window_manager_app_->host()->window()->RemovePreTargetHandler(this);
   }
 
   void CloseWindow(Id view_id) {

mojo/services/public/cpp/view_manager/lib/view_manager_test_suite.cc

@@ -4,6 +4,7 @@
 
 #include "mojo/services/public/cpp/view_manager/lib/view_manager_test_suite.h"
 
+#include "base/i18n/icu_util.h"
 #include "ui/gl/gl_surface.h"
 
 #if defined(USE_X11)
@@ -27,6 +28,9 @@ void ViewManagerTestSuite::Initialize() {
 
   base::TestSuite::Initialize();
   gfx::GLSurface::InitializeOneOffForTests();
+
+  // base::TestSuite and ViewsInit both try to load icu. That's ok for tests.
+  base::i18n::AllowMultipleInitializeCallsForTesting();
 }
 
 }  // namespace mojo