Hide the multi-window resizer if the resized window is hidden.

If one of the resized windows is hidden (visibility changes to hidden),
the multi-window resizer should also be hidden.

Bug: 894853
Change-Id: I77c8c5e831a85a6e66edb35381778d92e97cc856
Reviewed-on: https://chromium-review.googlesource.com/c/1282027
Commit-Queue: Xiaoqian Dai <xdai@chromium.org>
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Cr-Commit-Position: refs/heads/master@{#600181}

ash/wm/workspace/multi_window_resize_controller.cc

@@ -201,8 +201,7 @@ bool MultiWindowResizeController::ResizeWindows::Equals(
 MultiWindowResizeController::MultiWindowResizeController() = default;
 
 MultiWindowResizeController::~MultiWindowResizeController() {
-  window_resizer_.reset();
-  Hide();
+  ResetResizer();
 }
 
 void MultiWindowResizeController::Show(aura::Window* window,
@@ -235,39 +234,19 @@ void MultiWindowResizeController::Show(aura::Window* window,
                     &MultiWindowResizeController::ShowIfValidMouseLocation);
 }
 
-void MultiWindowResizeController::Hide() {
-  if (window_resizer_)
-    return;  // Ignore hides while actively resizing.
-
-  if (windows_.window1) {
-    StopObserving(windows_.window1);
-    windows_.window1 = nullptr;
-  }
-  if (windows_.window2) {
-    StopObserving(windows_.window2);
-    windows_.window2 = nullptr;
-  }
-
-  show_timer_.Stop();
-
-  if (!resize_widget_)
-    return;
-
-  for (size_t i = 0; i < windows_.other_windows.size(); ++i)
-    StopObserving(windows_.other_windows[i]);
-  mouse_watcher_.reset();
-  resize_widget_.reset();
-  windows_ = ResizeWindows();
-}
-
 void MultiWindowResizeController::MouseMovedOutOfHost() {
   Hide();
 }
 
+void MultiWindowResizeController::OnWindowVisibilityChanged(
+    aura::Window* window,
+    bool visible) {
+  if (!visible)
+    ResetResizer();
+}
+
 void MultiWindowResizeController::OnWindowDestroying(aura::Window* window) {
-  // Have to explicitly reset the WindowResizer, otherwise Hide() does nothing.
-  window_resizer_.reset();
-  Hide();
+  ResetResizer();
 }
 
 void MultiWindowResizeController::OnPostWindowStateTypeChange(
@@ -275,8 +254,7 @@ void MultiWindowResizeController::OnPostWindowStateTypeChange(
     mojom::WindowStateType old_type) {
   if (window_state->IsMaximized() || window_state->IsFullscreen() ||
       window_state->IsMinimized()) {
-    window_resizer_.reset();
-    Hide();
+    ResetResizer();
   }
 }
 
@@ -476,6 +454,37 @@ bool MultiWindowResizeController::IsShowing() const {
   return resize_widget_.get() || show_timer_.IsRunning();
 }
 
+void MultiWindowResizeController::Hide() {
+  if (window_resizer_)
+    return;  // Ignore hides while actively resizing.
+
+  if (windows_.window1) {
+    StopObserving(windows_.window1);
+    windows_.window1 = nullptr;
+  }
+  if (windows_.window2) {
+    StopObserving(windows_.window2);
+    windows_.window2 = nullptr;
+  }
+
+  show_timer_.Stop();
+
+  if (!resize_widget_)
+    return;
+
+  for (auto* window : windows_.other_windows)
+    StopObserving(window);
+  mouse_watcher_.reset();
+  resize_widget_.reset();
+  windows_ = ResizeWindows();
+}
+
+void MultiWindowResizeController::ResetResizer() {
+  // Have to explicitly reset the WindowResizer, otherwise Hide() does nothing.
+  window_resizer_.reset();
+  Hide();
+}
+
 void MultiWindowResizeController::StartResize(
     const gfx::Point& location_in_screen) {
   DCHECK(!window_resizer_.get());
@@ -543,8 +552,7 @@ void MultiWindowResizeController::CancelResize() {
     return;  // Happens if window was destroyed and we nuked the WindowResizer.
   window_resizer_->RevertDrag();
   wm::GetWindowState(window_resizer_->GetTarget())->DeleteDragDetails();
-  window_resizer_.reset();
-  Hide();
+  ResetResizer();
 }
 
 gfx::Rect MultiWindowResizeController::CalculateResizeWidgetBounds(

ash/wm/workspace/multi_window_resize_controller.h

@@ -45,13 +45,11 @@ class ASH_EXPORT MultiWindowResizeController
   // is over, |component| the edge and |point| the location of the mouse.
   void Show(aura::Window* window, int component, const gfx::Point& point);
 
-  // Hides the resize widget.
-  void Hide();
-
   // MouseWatcherListener:
   void MouseMovedOutOfHost() override;
 
   // WindowObserver:
+  void OnWindowVisibilityChanged(aura::Window* window, bool visible) override;
   void OnWindowDestroying(aura::Window* window) override;
 
   // wm::WindowStateObserver:
@@ -132,6 +130,12 @@ class ASH_EXPORT MultiWindowResizeController
   // Returns true if the widget is showing.
   bool IsShowing() const;
 
+  // Hides the resize widget.
+  void Hide();
+
+  // Resets the window resizer and hides the resize widget.
+  void ResetResizer();
+
   // Initiates a resize.
   void StartResize(const gfx::Point& location_in_screen);
 

ash/wm/workspace/multi_window_resize_controller_unittest.cc

@@ -406,6 +406,29 @@ TEST_F(MultiWindowResizeControllerTest, WindowStateChange) {
   EXPECT_FALSE(IsShowing());
 }
 
+// Tests that if one of the resized windows visibility changes to hidden, the
+// resize widget should be dismissed.
+TEST_F(MultiWindowResizeControllerTest, HideWindowTest) {
+  aura::test::TestWindowDelegate delegate1;
+  std::unique_ptr<aura::Window> w1(CreateTestWindowInShellWithDelegate(
+      &delegate1, -1, gfx::Rect(0, 0, 100, 100)));
+  delegate1.set_window_component(HTRIGHT);
+  aura::test::TestWindowDelegate delegate2;
+  std::unique_ptr<aura::Window> w2(CreateTestWindowInShellWithDelegate(
+      &delegate2, -2, gfx::Rect(100, 0, 100, 100)));
+  delegate2.set_window_component(HTLEFT);
+
+  ui::test::EventGenerator* generator = GetEventGenerator();
+  gfx::Point w1_center_in_screen = w1->GetBoundsInScreen().CenterPoint();
+  generator->MoveMouseTo(w1_center_in_screen);
+  ShowNow();
+  EXPECT_TRUE(IsShowing());
+
+  // Hide one window should dimiss the resizer.
+  w1->Hide();
+  EXPECT_FALSE(IsShowing());
+}
+
 namespace {
 
 class TestWindowStateDelegate : public wm::WindowStateDelegate {