overview: Correct for changes to the |kTopViewInset| window property.

The |kTopViewInset| window property can change during overview.
Particularly, the Settings window behaves that way if overview starts
during transition to tablet mode as another window carries over from
clamshell snapped state to tablet split view. Now, when the
|kTopViewInset| window property changes, consistent with existing
behavior for bounds changes, the visual appearance of overview shall
generally be corrected at the expense of interrupting animation effects.
The one exception is if the |kTopViewInset| window property changes
while overview is being prepared. In this case, still consistent with
existing behavior for bounds changes, nothing shall be done, because
when the overview preparation has been completed, overview will look
right anyway.

Test: ash_unittests OverviewSessionTest.TopViewInsetChangeDuringOverview
Bug: 932816
Change-Id: I482d5ce5c24ff40ccc28e898ae3668f6831b71bd
Reviewed-on: https://chromium-review.googlesource.com/c/1495444
Commit-Queue: Avery Musbach <amusbach@chromium.org>
Reviewed-by: Sammie Quon <sammiequon@chromium.org>
Cr-Commit-Position: refs/heads/master@{#636633}

ash/wm/overview/overview_grid.cc

@@ -919,6 +919,16 @@ void OverviewGrid::OnWindowBoundsChanged(aura::Window* window,
   PositionWindows(false);
 }
 
+void OverviewGrid::OnWindowPropertyChanged(aura::Window* window,
+                                           const void* key,
+                                           intptr_t old) {
+  if (prepared_for_overview_ && key == aura::client::kTopViewInset &&
+      window->GetProperty(aura::client::kTopViewInset) !=
+          static_cast<int>(old)) {
+    PositionWindows(/*animate=*/false);
+  }
+}
+
 void OverviewGrid::OnPostWindowStateTypeChange(
     wm::WindowState* window_state,
     mojom::WindowStateType old_type) {

ash/wm/overview/overview_grid.h

@@ -139,11 +139,15 @@ class ASH_EXPORT OverviewGrid : public aura::WindowObserver,
 
   // aura::WindowObserver:
   void OnWindowDestroying(aura::Window* window) override;
-  // TODO(flackr): Handle window bounds changed in OverviewItem.
+  // TODO(flackr): Handle window bounds changed in OverviewItem. See also
+  // OnWindowPropertyChanged() below.
   void OnWindowBoundsChanged(aura::Window* window,
                              const gfx::Rect& old_bounds,
                              const gfx::Rect& new_bounds,
                              ui::PropertyChangeReason reason) override;
+  void OnWindowPropertyChanged(aura::Window* window,
+                               const void* key,
+                               intptr_t old) override;
 
   // wm::WindowStateObserver:
   void OnPostWindowStateTypeChange(wm::WindowState* window_state,

ash/wm/overview/overview_session_unittest.cc

@@ -874,6 +874,19 @@ TEST_F(OverviewSessionTest, BoundsChangeDuringOverview) {
   ToggleOverview();
 }
 
+// Tests that a change to the |kTopViewInset| window property during overview is
+// corrected for.
+TEST_F(OverviewSessionTest, TopViewInsetChangeDuringOverview) {
+  std::unique_ptr<aura::Window> window = CreateTestWindow(gfx::Rect(400, 400));
+  window->SetProperty(aura::client::kTopViewInset, 32);
+  ToggleOverview();
+  gfx::Rect overview_bounds = GetTransformedTargetBounds(window.get());
+  window->SetProperty(aura::client::kTopViewInset, 0);
+  gfx::Rect new_overview_bounds = GetTransformedTargetBounds(window.get());
+  EXPECT_NE(overview_bounds, new_overview_bounds);
+  ToggleOverview();
+}
+
 // Tests that a newly created window aborts overview.
 TEST_F(OverviewSessionTest, NewWindowCancelsOverview) {
   std::unique_ptr<aura::Window> window1(CreateTestWindow());