[Ash] Only snap windows that can maximize.

ash/test/ash_test_base.cc

Index: ash/test/ash_test_base.cc
diff --git a/ash/test/ash_test_base.cc b/ash/test/ash_test_base.cc
index 166e2b7d007df4a1aebf69a5e40342c9c753bfae..c0dd6c0775abf43d9b967c06248e70471ac4f534 100644
--- a/ash/test/ash_test_base.cc
+++ b/ash/test/ash_test_base.cc
@@ -220,12 +220,18 @@ aura::Window* AshTestBase::CurrentContext() {
 }
 
 aura::Window* AshTestBase::CreateTestWindowInShellWithId(int id) {
-  return CreateTestWindowInShellWithDelegate(NULL, id, gfx::Rect());
+  return CreateTestWindowInShellWithDelegate(
+      aura::test::TestWindowDelegate::CreateSelfDestroyingDelegate(),
+      id,
+      gfx::Rect());
 }
 
 aura::Window* AshTestBase::CreateTestWindowInShellWithBounds(
     const gfx::Rect& bounds) {
-  return CreateTestWindowInShellWithDelegate(NULL, 0, bounds);
+  return CreateTestWindowInShellWithDelegate(
+      aura::test::TestWindowDelegate::CreateSelfDestroyingDelegate(),
+      0,
+      bounds);
 }
 
 aura::Window* AshTestBase::CreateTestWindowInShell(SkColor color,