Fix crash which occurs when a widget destroys itself as a result of ET_GESTURE_TAP_DOWN

ash/wm/caption_buttons/frame_maximize_button_unittest.cc

Index: ash/wm/caption_buttons/frame_maximize_button_unittest.cc
diff --git a/ash/wm/caption_buttons/frame_maximize_button_unittest.cc b/ash/wm/caption_buttons/frame_maximize_button_unittest.cc
index 3886416c6d2a041667c38cb30830a109c81b9306..c2908c5a84e488c28fe119477997f352476e7562 100644
--- a/ash/wm/caption_buttons/frame_maximize_button_unittest.cc
+++ b/ash/wm/caption_buttons/frame_maximize_button_unittest.cc
@@ -750,6 +750,36 @@ TEST_F(FrameMaximizeButtonTest, MaximizeSnapLeftRestore) {
   EXPECT_FALSE(window_state->HasRestoreBounds());
 }
 
+// Test hovering over the minimize button in the help bubble then tapping the
+// snap left button.
+TEST_F(FrameMaximizeButtonTest, MaximizeBubbleMouseHoverAndTouch) {
+  aura::Window* window = widget()->GetNativeWindow();
+  ash::FrameMaximizeButton* maximize_button =
+      FrameMaximizeButtonTest::maximize_button();
+  maximize_button->set_bubble_appearance_delay_ms(0);
+
+  // Move the mouse cursor over the maximize button to make the help bubble
+  // appear.
+  aura::test::EventGenerator generator(window->GetRootWindow());
+  generator.MoveMouseTo(maximize_button->GetBoundsInScreen().CenterPoint());
+  MaximizeBubbleController* maximizer = maximize_button->maximizer();
+  ASSERT_TRUE(maximizer);
+
+  // Move the mouse cursor over the minimize button in the help bubble.
+  gfx::Point minimize_pos = maximizer->GetButtonForUnitTest(SNAP_MINIMIZE)->
+      GetBoundsInScreen().CenterPoint();
+  generator.MoveMouseTo(minimize_pos);
+
+  // Tap the snap left button in the help bubble.
+  gfx::Point snap_pos = maximizer->GetButtonForUnitTest(SNAP_LEFT)->
+      GetBoundsInScreen().CenterPoint();
+  generator.GestureTapAt(snap_pos);
+  internal::SnapSizer sizer(wm::GetWindowState(window), gfx::Point(),
+      internal::SnapSizer::LEFT_EDGE,
+      internal::SnapSizer::OTHER_INPUT);
+  EXPECT_EQ(sizer.target_bounds().ToString(), window->bounds().ToString());
+}
+
 // Test that minimizing the window per keyboard closes the maximize bubble.
 TEST_F(FrameMaximizeButtonTest, MinimizePerKeyClosesBubble) {
   aura::Window* window = widget()->GetNativeWindow();