Draggable peeking/fullscreen launcher with transparent background.

ui/app_list/views/app_list_view.h

Index: ui/app_list/views/app_list_view.h
diff --git a/ui/app_list/views/app_list_view.h b/ui/app_list/views/app_list_view.h
index 3b6571411d9f20e5bd753b8cf8e0cf31133b338d..766bf6a19f5f747e18ae3757e37ba64a16aa3f61 100644
--- a/ui/app_list/views/app_list_view.h
+++ b/ui/app_list/views/app_list_view.h
@@ -9,12 +9,18 @@
 
 #include "base/callback.h"
 #include "base/macros.h"
+#include "base/scoped_observer.h"
 #include "build/build_config.h"
 #include "ui/app_list/app_list_export.h"
 #include "ui/app_list/speech_ui_model_observer.h"
+#include "ui/display/display_observer.h"
 #include "ui/views/bubble/bubble_dialog_delegate.h"
 #include "ui/views/widget/widget.h"
 
+namespace display {
+class Screen;
+}
+
 namespace app_list {
 class ApplicationDragAndDropHost;
 class AppListMainView;
@@ -32,8 +38,11 @@ class AppListViewTestApi;
 // AppListView is the top-level view and controller of app list UI. It creates
 // and hosts a AppsGridView and passes AppListModel to it for display.
 class APP_LIST_EXPORT AppListView : public views::BubbleDialogDelegateView,
-                                    public SpeechUIModelObserver {
+                                    public SpeechUIModelObserver,
+                                    public display::DisplayObserver {
  public:
+  enum AppListState { INITIAL = 0, PEEKING, FULLSCREEN };

[msw, 2017/06/07 02:31:39]

Comment on this enum and each of its states, the concept of peeking and
fullscreen app list states are new and will be unfamiliar to most readers. Also,
replace INITIAL with CLOSED (or remove INITIAL and initialize |app_list_state_|
to the actual peeking/fullscreen initial state when the view is constructed)?

[newcomer, 2017/06/07 17:21:37]

Done.

+
   // Does not take ownership of |delegate|.
   explicit AppListView(AppListViewDelegate* delegate);
   ~AppListView() override;
@@ -89,6 +98,13 @@ class APP_LIST_EXPORT AppListView : public views::BubbleDialogDelegateView,
   void Layout() override;
   void SchedulePaintInRect(const gfx::Rect& rect) override;
 
+  // Changes the view to the peeking state or to the fullscreen state.
+  void ToFullscreen();

[msw, 2017/06/07 02:31:39]

Remove these now that we have ChangeState/SetState.

[newcomer, 2017/06/07 17:21:38]

Done.

+  void ToPeeking();
+  void ChangeState(AppListState new_state);

[msw, 2017/06/07 02:31:39]

Rename this SetState

[newcomer, 2017/06/07 17:21:38]

Done.

+
+  bool IsFullscreen() const;

[msw, 2017/06/07 02:31:39]

Change this to |AppListState app_list_state() const { return app_list_state_; }
You can optionally also/instead do |bool is_fullscreen() const { return
app_list_state_ == FULLSCREEN; }

[newcomer, 2017/06/07 17:21:38]

I think having both is a good idea. Thanks!

+
  private:
   friend class test::AppListViewTestApi;
 
@@ -102,6 +118,17 @@ class APP_LIST_EXPORT AppListView : public views::BubbleDialogDelegateView,
   // Initializes the widget as a bubble.
   void InitializeBubble(gfx::NativeView parent, int initial_apps_page);
 
+  // Initializes |initial_drag_point_|.
+  void StartDrag(const gfx::Point& location);
+
+  // Updates the bounds of the widget while maintaining the relative position
+  // of the top of the widget and the gesture.
+  void UpdateDrag(const gfx::Point& location);
+
+  // Handles app list state transfers. If the drag was fast enough, ignore the
+  // release position and snap to the next state.
+  void EndDrag(const gfx::Point& location);
+
   // Overridden from views::BubbleDialogDelegateView:
   void OnBeforeBubbleWidgetInit(views::Widget::InitParams* params,
                                 views::Widget* widget) const override;
@@ -112,6 +139,10 @@ class APP_LIST_EXPORT AppListView : public views::BubbleDialogDelegateView,
   bool WidgetHasHitTestMask() const override;
   void GetWidgetHitTestMask(gfx::Path* mask) const override;
 
+  // Overridden from ui::EventHandler:
+  void OnMouseEvent(ui::MouseEvent* event) override;
+  void OnGestureEvent(ui::GestureEvent* event) override;
+
   // Overridden from views::WidgetObserver:
   void OnWidgetDestroying(views::Widget* widget) override;
   void OnWidgetVisibilityChanged(views::Widget* widget, bool visible) override;
@@ -120,14 +151,43 @@ class APP_LIST_EXPORT AppListView : public views::BubbleDialogDelegateView,
   void OnSpeechRecognitionStateChanged(
       SpeechRecognitionState new_state) override;
 
+  // Overridden from DisplayObserver:
+  void OnDisplayMetricsChanged(const display::Display& display,
+                               uint32_t changed_metrics) override;
+
   AppListViewDelegate* delegate_;  // Weak. Owned by AppListService.
 
   AppListMainView* app_list_main_view_;
   SpeechView* speech_view_;
+  views::Widget* fullscreen_widget_ = nullptr;  // Owned by AppListView.
 
   views::View* search_box_focus_host_;  // Owned by the views hierarchy.
   views::Widget* search_box_widget_;    // Owned by the app list's widget.
   SearchBoxView* search_box_view_;      // Owned by |search_box_widget_|.
+  // Owned by the app list's widget. Null if the fullscreen app list is not
+  // enabled.
+  views::View* app_list_background_shield_ = nullptr;
+  // The gap between the initial gesture event and the top of the window.
+  gfx::Point initial_drag_point_;
+  // The velocity of the gesture event.
+  float last_fling_velocity_ = 0;
+  // The default y coordinate of the current state of the app list. Changes
+  // based on the app list state and screen orientation.
+  int default_peeking_y_ = 0;

[msw, 2017/06/07 02:31:39]

Remove this, it's no longer used.

[newcomer, 2017/06/07 17:21:38]

Done.

+  bool is_fullscreen_app_list_ = false;

[msw, 2017/06/07 02:31:39]

Remove this, it's no longer used.

[newcomer, 2017/06/07 17:21:38]

Done.

+  // Flag temporarily used to prevent repeated calls to
+  // features::IsFullscreenAppListEnabled.
+  bool is_fullscreen_app_list_enabled_ = false;

[msw, 2017/06/07 02:31:39]

Move this to a file-local function in cc file's anon namespace, like:
bool IsFullscreenAppListEnabled() {
  // Cache this value to avoid repeated lookup.
  static bool cached_value = features::IsFullscreenAppListEnabled();
  return cached_value;
}

[newcomer, 2017/06/07 17:21:38]

Done.

+  // The desktop area, not including the shelf.
+  gfx::Rect display_work_area_bounds_;

[msw, 2017/06/07 02:31:39]

Remove this, it's no longer used.

[newcomer, 2017/06/07 17:21:38]

Done.

+  // The bounds of the app list. The size should never change, only the
+  // position.
+  gfx::Rect fullscreen_widget_bounds_;

[msw, 2017/06/07 02:31:39]

Remove this, it's no longer used.

[newcomer, 2017/06/07 17:21:37]

Done.

+  // The state of the app list, controlled via ChangeState().

[msw, 2017/06/07 02:31:39]

Update ChangeState -> SetState if you accept that rename, or just remove ",
controlled via ChangeState()"

[newcomer, 2017/06/07 17:21:37]

Done.

+  AppListState app_list_state_;

[msw, 2017/06/07 02:31:39]

Initialize this value here or in the constructor.

[newcomer, 2017/06/07 17:21:38]

Initialized in the constructor.

+
+  // An observer that notifies AppListView when the display has changed.
+  ScopedObserver<display::Screen, display::DisplayObserver> display_observer_;
 
   // A semi-transparent white overlay that covers the app list while dialogs are
   // open.