Moves maintaining ShellObservers back to Shell

ash/shell.h

Index: ash/shell.h
diff --git a/ash/shell.h b/ash/shell.h
index f17b9a7ff4f43451afc62a32461332619be0d26f..a9d11f55a0d2f5b0938febd50c37cac31c572d1d 100644
--- a/ash/shell.h
+++ b/ash/shell.h
@@ -108,6 +108,7 @@ class ScreenPinningController;
 class ScreenPositionController;
 class SessionStateDelegate;
 struct ShellInitParams;
+class ShellObserver;
 class ShutdownObserver;
 class SmsObserver;
 class StickyKeysController;
@@ -409,6 +410,47 @@ class ASH_EXPORT Shell : public SystemModalContainerEventFilterDelegate,
 
   GPUSupport* gpu_support() { return gpu_support_.get(); }
 
+  void AddShellObserver(ShellObserver* observer);
+  void RemoveShellObserver(ShellObserver* observer);
+
+  // Called after maximize mode has started, windows might still animate though.
+  void OnMaximizeModeStarted();

[msw, 2017/03/08 19:52:23]

optional nit: wdyt about renaming these On* to Notify* (or vice versa)?

[sky, 2017/03/08 20:26:06]

Done.

+
+  // Called after maximize mode is about to end.
+  void OnMaximizeModeEnding();
+
+  // Called after maximize mode has ended, windows might still be returning to
+  // their original position.
+  void OnMaximizeModeEnded();
+
+  // Called when the overview mode is about to be started (before the windows
+  // get re-arranged).
+  void OnOverviewModeStarting();
+
+  // Called after overview mode has ended.
+  void OnOverviewModeEnded();
+
+  // Notify observers that fullscreen mode has changed for |root_window|.
+  void NotifyFullscreenStateChanged(bool is_fullscreen, WmWindow* root_window);
+
+  // Notify observers that |pinned_window| changed its pinned window state.
+  void NotifyPinnedStateChanged(WmWindow* pinned_window);
+
+  // Notify observers that the virtual keyboard has been activated/deactivated.
+  void NotifyVirtualKeyboardActivated(bool activated);
+
+  // Notify observers that the shelf was created for |root_window|.
+  // TODO(jamescook): Move to Shelf.
+  void NotifyShelfCreatedForRootWindow(WmWindow* root_window);
+
+  // Notify observers that |root_window|'s shelf changed auto-hide alignment.

[msw, 2017/03/08 19:52:23]

nit: remove 'auto-hide' (was wrong previously)

[sky, 2017/03/08 20:26:06]

Done.

+  // TODO(jamescook): Move to Shelf.
+  void NotifyShelfAlignmentChanged(WmWindow* root_window);
+
+  // Notify observers that |root_window|'s shelf changed auto-hide behavior.
+  // TODO(jamescook): Move to Shelf.
+  void NotifyShelfAutoHideBehaviorChanged(WmWindow* root_window);
+
  private:
   FRIEND_TEST_ALL_PREFIXES(ExtendedDesktopTest, TestCursor);
   FRIEND_TEST_ALL_PREFIXES(WindowManagerTest, MouseEventCursors);
@@ -571,6 +613,8 @@ class ASH_EXPORT Shell : public SystemModalContainerEventFilterDelegate,
 
   std::unique_ptr<AppListDelegateImpl> app_list_delegate_impl_;
 
+  base::ObserverList<ShellObserver> shell_observers_;
+
   DISALLOW_COPY_AND_ASSIGN(Shell);
 };