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#include "chrome/views/external_focus_tracker.h"

#include "chrome/views/view.h"
#include "chrome/views/view_storage.h"

namespace ChromeViews {

ExternalFocusTracker::ExternalFocusTracker(
    ChromeViews::View* parent_view, ChromeViews::FocusManager* focus_manager)
    : focus_manager_(focus_manager),
      parent_view_(parent_view) {
  view_storage_ = ChromeViews::ViewStorage::GetSharedInstance();
  last_focused_view_storage_id_ = view_storage_->CreateStorageID();
  // Store the view which is focused when we're created.
  StartTracking();
}

ExternalFocusTracker::~ExternalFocusTracker() {
  view_storage_->RemoveView(last_focused_view_storage_id_);
  if (focus_manager_)
    focus_manager_->RemoveFocusChangeListener(this);
}

void ExternalFocusTracker::FocusWillChange(View* focused_before,
                                           View* focused_now) {
  if (focused_now && !parent_view_->IsParentOf(focused_now) &&
      parent_view_ != focused_now) {
    // Store the newly focused view.
    StoreLastFocusedView(focused_now);
  }
}

void ExternalFocusTracker::FocusLastFocusedExternalView() {
  View* last_focused_view =
      view_storage_->RetrieveView(last_focused_view_storage_id_);
  if (last_focused_view)
    last_focused_view->RequestFocus();
}

void ExternalFocusTracker::SetFocusManager(
    ChromeViews::FocusManager* focus_manager) {
  if (focus_manager_)
    focus_manager_->RemoveFocusChangeListener(this);
  focus_manager_ = focus_manager;
  if (focus_manager_)
    StartTracking();
}

void ExternalFocusTracker::StoreLastFocusedView(View* view) {
  view_storage_->RemoveView(last_focused_view_storage_id_);
  // If the view is NULL, remove the last focused view from storage, but don't
  // try to store NULL.
  if (view != NULL)
    view_storage_->StoreView(last_focused_view_storage_id_, view);
}

void ExternalFocusTracker::StartTracking() {
  StoreLastFocusedView(focus_manager_->GetFocusedView());
  focus_manager_->AddFocusChangeListener(this);
}

} // namespace