mus: move View Manager to components/mus/vm

components/mus/focus_controller.cc

-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "components/mus/focus_controller.h"
-
-#include "components/mus/focus_controller_delegate.h"
-#include "components/mus/server_view.h"
-#include "components/mus/server_view_drawn_tracker.h"
-
-namespace mus {
-
-FocusController::FocusController(FocusControllerDelegate* delegate)
-    : delegate_(delegate) {}
-
-FocusController::~FocusController() {}
-
-void FocusController::SetFocusedView(ServerView* view) {
-  if (GetFocusedView() == view)
-    return;
-
-  SetFocusedViewImpl(view, CHANGE_SOURCE_EXPLICIT);
-}
-
-ServerView* FocusController::GetFocusedView() {
-  return drawn_tracker_ ? drawn_tracker_->view() : nullptr;
-}
-
-void FocusController::SetFocusedViewImpl(ServerView* view,
-                                         ChangeSource change_source) {
-  ServerView* old = GetFocusedView();
-
-  DCHECK(!view || view->IsDrawn());
-
-  if (view)
-    drawn_tracker_.reset(new ServerViewDrawnTracker(view, this));
-  else
-    drawn_tracker_.reset();
-
-  if (change_source == CHANGE_SOURCE_DRAWN_STATE_CHANGED)
-    delegate_->OnFocusChanged(old, view);
-}
-
-void FocusController::OnDrawnStateChanged(ServerView* ancestor,
-                                          ServerView* view,
-                                          bool is_drawn) {
-  DCHECK(!is_drawn);  // We only observe when drawn.
-  SetFocusedViewImpl(ancestor, CHANGE_SOURCE_DRAWN_STATE_CHANGED);
-}
-
-}  // namespace mus