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 cbdb1d895728135ba6ba8995b4aa480b4bcfaabb..c88d47738ac7ba08a3ceec923f5032c6942b5848 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;
@@ -32,7 +38,8 @@ 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:
   // Does not take ownership of |delegate|.
   explicit AppListView(AppListViewDelegate* delegate);
@@ -62,6 +69,8 @@ class APP_LIST_EXPORT AppListView : public views::BubbleDialogDelegateView,
 
   void UpdateBounds();
 
+  void UpdateDimensions();
+
   // Enables/disables a semi-transparent overlay over the app list (good for
   // hiding the app list when a modal dialog is being shown).
   void SetAppListOverlayVisible(bool visible);
@@ -89,6 +98,12 @@ 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();
+  void ToPeeking();
+
+  bool IsFullscreen() const;
+
  private:
   friend class test::AppListViewTestApi;
 
@@ -102,6 +117,20 @@ class APP_LIST_EXPORT AppListView : public views::BubbleDialogDelegateView,
   // Initializes the widget as a bubble.
   void InitializeBubble(gfx::NativeView parent, int initial_apps_page);
 
+  // Transfers drag events to Start/Update/EndDrag.
+  void HandleDrag(const gfx::Point& location, ui::EventType type);
+
+  // Initializes |initial_drag_separation_|.
+  void StartDrag(const gfx::Point& location);

[vadimt, 2017/05/26 23:44:08]

You don't need to declare StartDrag in .h file.
Anonymous namespace in .cc.

[newcomer, 2017/05/30 21:37:03]

Done. Also moved HandleDrag, UpdateDrag, and EndDrag.

+
+  // 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 launcher 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 +141,10 @@ 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 +153,40 @@ 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.
+  views::View* launcher_background_shield_ = nullptr;
+  // The gap between the initial gesture event and the top of the window.
+  int initial_drag_separation_ = 0;
+  // The velocity of the gesture event.
+  float last_fling_velocity_ = 0;
+  // The height of the peeking launcher, which changes based on screen
+  // orientation.
+  int default_peeking_launcher_y_ = 0;
+  // The DIP delta that must be exceeded for the launcher to snap to the next
+  // state.
+  int launcher_threshold_ = 0;
+  bool is_fullscreen_launcher_ = false;
+  // The desktop area, not including the shelf.
+  gfx::Rect display_work_area_bounds_;
+  // The bounds of the launcher. The size should never change, only the
+  // position.
+  gfx::Rect fullscreen_widget_bounds_;
+
+  // 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.