CrOS Tablet Window management - Split Screen part I

ash/shell.h

Index: ash/shell.h
diff --git a/ash/shell.h b/ash/shell.h
index 45a69951e18e7539eb809f9c995188e446e9096f..9d96df72e3452955972462cd768d4ee681bfde69 100644
--- a/ash/shell.h
+++ b/ash/shell.h
@@ -151,6 +151,7 @@ class ShellObserver;
 class ShutdownController;
 class ShutdownObserver;
 class SmsObserver;
+class SplitViewController;
 class StickyKeysController;
 class SystemGestureEventFilter;
 class SystemModalContainerEventFilter;
@@ -541,6 +542,13 @@ class ASH_EXPORT Shell : public SessionObserver,
 
   GPUSupport* gpu_support() { return gpu_support_.get(); }
 
+  SplitViewController* split_view_controller() {
+    return split_view_controller_.get();
+  }
+
+  // Returns true if split view mode is active.
+  bool IsSplitViewModeActive() const;
+
   void AddShellObserver(ShellObserver* observer);
   void RemoveShellObserver(ShellObserver* observer);
 
@@ -582,6 +590,13 @@ class ASH_EXPORT Shell : public SessionObserver,
   // Notifies observers that overview mode has ended.
   void NotifyOverviewModeEnded();
 
+  // Notifies observers that split view mode is about to be started (before the
+  // window gets snapped and activated).
+  void NotifySplitViewModeStarting();
+
+  // Notifies observers that split view mode has ended.
+  void NotifySplitViewModeEnded();
+
   // Notifies observers that fullscreen mode has changed for |root_window|.
   void NotifyFullscreenStateChanged(bool is_fullscreen,
                                     aura::Window* root_window);
@@ -805,6 +820,9 @@ class ASH_EXPORT Shell : public SessionObserver,
   std::unique_ptr<PartialMagnificationController>
       partial_magnification_controller_;
 
+  // The split view controller for Chrome OS in tablet mode.
+  std::unique_ptr<SplitViewController> split_view_controller_;
+
   // |native_cursor_manager_| is owned by |cursor_manager_|, but we keep a
   // pointer to vend to test code.
   AshNativeCursorManager* native_cursor_manager_;