Always create a backdrop for fullscreen/maximized arc window.

Arc window may be cropped, which can cause showing/hiding
backdrop during the transition, which then may send
unnecessary synthesized mouse move even.

Bug: b/111319005
Test: Covered by unit test. Also tested on play music. See bug for repro step.

Change-Id: Ie030e24095eeadbd549e7cdc8cf7be0438c88d49
Reviewed-on: https://chromium-review.googlesource.com/1162705Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Commit-Queue: Mitsuru Oshima <oshima@chromium.org>
Cr-Commit-Position: refs/heads/master@{#581086}

components/exo/client_controlled_shell_surface.cc

@@ -511,7 +511,7 @@ void ClientControlledShellSurface::OnBoundsChangeEvent(
 
     // The client's geometry uses fullscreen in client controlled,
     // (but the surface is placed under the frame), so just use
-    // the window bounds instead for maximixed stte.
+    // the window bounds instead for maximixed state.
     gfx::Rect client_bounds =
         widget_->IsMaximized()
             ? window_bounds
@@ -615,7 +615,6 @@ bool ClientControlledShellSurface::IsInputEnabled(Surface* surface) const {
 
 void ClientControlledShellSurface::OnSetFrame(SurfaceFrameType type) {
   ShellSurfaceBase::OnSetFrame(type);
-  frame_type_ = type;
   UpdateAutoHideFrame();
 }
 
@@ -955,11 +954,11 @@ void ClientControlledShellSurface::UpdateCaptionButtonModel() {
 
 void ClientControlledShellSurface::UpdateBackdrop() {
   aura::Window* window = widget_->GetNativeWindow();
-  const display::Display display =
-      display::Screen::GetScreen()->GetDisplayNearestWindow(window);
-  bool enable_backdrop =
-      (widget_->IsFullscreen() || widget_->IsMaximized()) &&
-      !widget_->GetWindowBoundsInScreen().Contains(display.work_area());
+
+  // Always create a backdrop regardless of the geometry because
+  // maximized/fullscreen widget's geometry can be cropped.
+  bool enable_backdrop = (widget_->IsFullscreen() || widget_->IsMaximized());
+
   ash::BackdropWindowMode target_backdrop_mode =
       enable_backdrop ? ash::BackdropWindowMode::kEnabled
                       : ash::BackdropWindowMode::kAuto;

components/exo/client_controlled_shell_surface_unittest.cc

@@ -28,6 +28,7 @@
 #include "ash/wm/window_util.h"
 #include "ash/wm/wm_event.h"
 #include "ash/wm/workspace_controller_test_api.h"
+#include "base/run_loop.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/test/scoped_feature_list.h"
 #include "cc/paint/display_item_list.h"
@@ -41,6 +42,7 @@
 #include "components/exo/wm_helper.h"
 #include "third_party/skia/include/utils/SkNoDrawCanvas.h"
 #include "ui/aura/client/aura_constants.h"
+#include "ui/aura/env.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_event_dispatcher.h"
 #include "ui/aura/window_tree_host.h"
@@ -520,6 +522,7 @@ TEST_F(ClientControlledShellSurfaceTest, Frame) {
 
   // AutoHide
   surface->SetFrame(SurfaceFrameType::AUTOHIDE);
+  surface->Commit();
   EXPECT_TRUE(frame_view->visible());
   EXPECT_EQ(fullscreen_bounds, widget->GetWindowBoundsInScreen());
   EXPECT_EQ(fullscreen_bounds,
@@ -554,6 +557,61 @@ TEST_F(ClientControlledShellSurfaceTest, Frame) {
             frame_view->GetClientBoundsForWindowBounds(client_bounds));
 }
 
+namespace {
+
+class TestEventHandler : public ui::EventHandler {
+ public:
+  TestEventHandler() = default;
+  ~TestEventHandler() override = default;
+
+  // ui::EventHandler:
+  void OnMouseEvent(ui::MouseEvent* event) override { received_event_ = true; }
+
+  bool received_event() const { return received_event_; }
+
+ private:
+  bool received_event_ = false;
+  DISALLOW_COPY_AND_ASSIGN(TestEventHandler);
+};
+
+}  // namespace
+
+TEST_F(ClientControlledShellSurfaceTest, NoSynthesizedEventOnFrameChange) {
+  UpdateDisplay("800x600");
+
+  gfx::Size buffer_size(256, 256);
+  std::unique_ptr<Buffer> buffer(
+      new Buffer(exo_test_helper()->CreateGpuMemoryBuffer(buffer_size)));
+  std::unique_ptr<Surface> surface(new Surface);
+
+  gfx::Rect fullscreen_bounds(0, 0, 800, 600);
+
+  auto shell_surface =
+      exo_test_helper()->CreateClientControlledShellSurface(surface.get());
+  surface->Attach(buffer.get());
+  surface->SetFrame(SurfaceFrameType::NORMAL);
+  surface->Commit();
+
+  // Maximized
+  shell_surface->SetMaximized();
+  shell_surface->SetGeometry(fullscreen_bounds);
+  surface->Commit();
+
+  // AutoHide
+  base::RunLoop().RunUntilIdle();
+  auto* env = aura::Env::GetInstance();
+  gfx::Rect cropped_fullscreen_bounds(0, 0, 800, 400);
+  env->SetLastMouseLocation(gfx::Point(100, 100));
+  TestEventHandler handler;
+  env->AddPreTargetHandler(&handler);
+  surface->SetFrame(SurfaceFrameType::AUTOHIDE);
+  shell_surface->SetGeometry(cropped_fullscreen_bounds);
+  surface->Commit();
+  base::RunLoop().RunUntilIdle();
+  EXPECT_FALSE(handler.received_event());
+  env->RemovePreTargetHandler(&handler);
+}
+
 TEST_F(ClientControlledShellSurfaceTest, CompositorLockInRotation) {
   UpdateDisplay("800x600");
   const gfx::Size buffer_size(800, 600);
@@ -691,11 +749,11 @@ TEST_F(ClientControlledShellSurfaceTest, Maximize) {
   EXPECT_TRUE(HasBackdrop());
   EXPECT_TRUE(shell_surface->GetWidget()->IsMaximized());
 
-  // Enable backdrop only if the shell surface doesn't cover the display.
+  // We always show backdrop because the window may be cropped.
   display::Display display = display::Screen::GetScreen()->GetPrimaryDisplay();
   shell_surface->SetGeometry(display.bounds());
   surface->Commit();
-  EXPECT_FALSE(HasBackdrop());
+  EXPECT_TRUE(HasBackdrop());
 
   shell_surface->SetGeometry(gfx::Rect(0, 0, 100, display.bounds().height()));
   surface->Commit();
@@ -754,11 +812,11 @@ TEST_F(ClientControlledShellSurfaceTest, SetFullscreen) {
   surface->Commit();
   EXPECT_TRUE(HasBackdrop());
 
-  // Enable backdrop only if the shell surface doesn't cover the display.
+  // We always show backdrop becaues the window can be cropped.
   display::Display display = display::Screen::GetScreen()->GetPrimaryDisplay();
   shell_surface->SetGeometry(display.bounds());
   surface->Commit();
-  EXPECT_FALSE(HasBackdrop());
+  EXPECT_TRUE(HasBackdrop());
 
   shell_surface->SetGeometry(gfx::Rect(0, 0, 100, display.bounds().height()));
   surface->Commit();