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..5549f26dd97f4e2805f7f78c4c93d06d97d17817 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;
@@ -32,15 +38,28 @@ 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 {
+    // If set, closes |app_list_main_view_| and dismisses the delegate.
+    CLOSED = 0,
+
+    // The initial state for the app list. If set, the widget will peek over
+    // the shelf by KPeekingAppListHeight DIPs.

[msw, 2017/06/07 17:44:06]

Lowercase 'k'

[newcomer, 2017/06/07 19:01:42]

Done.

+    PEEKING,
+
+    // If set, the widget will be repositioned to take up the whole screen.
+    FULLSCREEN

[msw, 2017/06/07 17:44:06]

optional nit: a trailing comma indicates that it's okay to add new states.

[newcomer, 2017/06/07 19:01:42]

Done.

+  };
+
   // Does not take ownership of |delegate|.
   explicit AppListView(AppListViewDelegate* delegate);
   ~AppListView() override;
 
-  // Initializes the widget as a bubble or fullscreen view depending on the
-  // presence of a cmd line switch. parent and initial_apps_page are used for
-  // both the bubble and fullscreen initialization.
+  // Initializes the widget as a bubble or fullscreen view depending on if the
+  // fullscreen app list feature is set. |parent| and |initial_apps_page| are
+  // used for both the bubble and fullscreen initialization.
   void Initialize(gfx::NativeView parent, int initial_apps_page);
 
   void SetBubbleArrow(views::BubbleBorder::Arrow arrow);
@@ -58,8 +77,6 @@ class APP_LIST_EXPORT AppListView : public views::BubbleDialogDelegateView,
   // timer to show the UI when a maximum allowed wait time has expired.
   void ShowWhenReady();
 
-  void CloseAppList();
-
   void UpdateBounds();
 
   // Enables/disables a semi-transparent overlay over the app list (good for
@@ -89,6 +106,12 @@ class APP_LIST_EXPORT AppListView : public views::BubbleDialogDelegateView,
   void Layout() override;
   void SchedulePaintInRect(const gfx::Rect& rect) override;
 
+  // Changes the app list state.
+  void SetState(AppListState new_state);
+
+  bool IsFullscreen() const { return app_list_state_ == FULLSCREEN; }

[msw, 2017/06/07 17:44:06]

nit: |is_fullscreen| for inline simple accessors/helpers.

[newcomer, 2017/06/07 19:01:42]

Done.

+  AppListState app_list_state() const { return app_list_state_; }
+
  private:
   friend class test::AppListViewTestApi;
 
@@ -102,6 +125,17 @@ 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 +146,10 @@ 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 +158,31 @@ 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 state of the app list, controlled via SetState().
+  AppListState app_list_state_;
+
+  // 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.