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..4c127ba331d8c9a1a34e098021e142c6da924f6c 100644
--- a/ui/app_list/views/app_list_view.h
+++ b/ui/app_list/views/app_list_view.h
@@ -12,6 +12,7 @@
 #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"
 
@@ -32,7 +33,8 @@ 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);
@@ -86,9 +88,18 @@ class APP_LIST_EXPORT AppListView : public views::BubbleDialogDelegateView,
 
   // Overridden from views::View:
   bool AcceleratorPressed(const ui::Accelerator& accelerator) override;
+
+  void ComputeConstants();

[vadimt, 2017/05/22 23:36:58]

Please don't place it between views::View overrides.

[newcomer, 2017/05/25 23:10:53]

Done.

+
   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();

[vadimt, 2017/05/22 23:36:58]

I assume there are 2 states Fullscreen and peeking. Then we need to have a
matching SetFullScreen(bool), not ToFullScreen/ToPeeking pair.

[newcomer, 2017/05/25 23:10:53]

In the next CL there will be five states (INITIAL, PEEKING, HALF,
FULLSCREEN_ALL_APPS, and FULLSCREEN_SEARCH). Can I push this to the next CL? It
will have to get refactored in the next CL anyways.

[vadimt, 2017/05/26 01:27:56]

Acknowledged.

+
  private:
   friend class test::AppListViewTestApi;
 
@@ -112,6 +123,17 @@ class APP_LIST_EXPORT AppListView : public views::BubbleDialogDelegateView,
   bool WidgetHasHitTestMask() const override;
   void GetWidgetHitTestMask(gfx::Path* mask) const override;
 
+  // Both OnMouseEvent and OnGestureEvent check to see if their events are
+  // drag events, if so the events are sent to HandleDrag which holds all
+  // AppListView drag logic.
+  void OnMouseEvent(ui::MouseEvent* event) override;

[vadimt, 2017/05/22 23:36:58]

You don't need comments for overrides. BTW are they overrides for
views::WidgetDelegateView?

[newcomer, 2017/05/25 23:10:53]

They are ui::EventHandler overrides. Done!

+  void OnGestureEvent(ui::GestureEvent* event) override;
+
+  // Handles all drag logic for the app list view. Touch and Click events are
+  // filtered through OnMouseEvent and OnGestureEvent before being passed to
+  // HandleDrag.
+  void HandleDrag(gfx::Point location, ui::EventType type);

[vadimt, 2017/05/22 23:36:58]

Is this override? If so, add override keyword; else, move.

[newcomer, 2017/05/25 23:10:53]

Done.

+
   // Overridden from views::WidgetObserver:
   void OnWidgetDestroying(views::Widget* widget) override;
   void OnWidgetVisibilityChanged(views::Widget* widget, bool visible) override;
@@ -120,14 +142,28 @@ 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_;
 
   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_|.
+  views::View* launcher_background_shield_;  // Owned by the app list's widget.

[vadimt, 2017/05/22 23:36:58]

I assume all added fields can't be made const fields?

[xiyuan, 2017/05/24 18:28:18]

Initialize it to nullptr,

i.e.
  views::View* launcher_background_shield_ = nullptr

So that we can use |launcher_background_shield_| in Layout etc instead of
checking fullscreen feature everywhere.

[newcomer, 2017/05/25 23:10:53]

Correct.

[newcomer, 2017/05/25 23:10:53]

Done.

+
+  int initial_drag_separation_;

[vadimt, 2017/05/22 23:36:58]

I know that other fields don't have comments, but it's hard to deduce the
meaning from the name. Please add comments for all added fields.

[newcomer, 2017/05/25 23:10:53]

Done.

+  float last_fling_velocity_;
+  int default_peeking_launcher_y_;
+  int launcher_threshold_;
+  bool is_fullscreen_launcher_;
+  gfx::Rect display_work_area_bounds_;
+  gfx::Rect fullscreen_widget_bounds_;
 
   // A semi-transparent white overlay that covers the app list while dialogs are
   // open.