Show Media Router toolbar icon ephemerally for MR dialogs

chrome/browser/ui/webui/media_router/media_router_dialog_controller_impl.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 "chrome/browser/ui/webui/media_router/media_router_dialog_controller_impl.h"
 
 #include <memory>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "base/macros.h"
 #include "base/trace_event/trace_event.h"
 #include "build/build_config.h"
+#include "chrome/browser/media/router/media_router_ui_service.h"
 #include "chrome/browser/media/router/presentation_service_delegate_impl.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser_finder.h"
 #include "chrome/browser/ui/browser_window.h"
 #include "chrome/browser/ui/toolbar/media_router_action.h"
 #include "chrome/browser/ui/webui/constrained_web_dialog_ui.h"
 #include "chrome/browser/ui/webui/media_router/media_router_ui.h"
 #include "chrome/common/url_constants.h"
 #include "components/guest_view/browser/guest_view_base.h"
 #include "components/web_modal/web_contents_modal_dialog_host.h"
@@ skipping 78 matching lines @@
     return false;
   }
 
  private:
   base::WeakPtr<MediaRouterAction> action_;
   base::WeakPtr<MediaRouterDialogControllerImpl> controller_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaRouterDialogDelegate);
 };
 
+MediaRouterActionController* GetActionController(WebContents* web_contents) {
+  Profile* profile =
+      Profile::FromBrowserContext(web_contents->GetBrowserContext());
+  return MediaRouterUIService::Get(profile)->action_controller();
+}
+
 }  // namespace
 
 // static
 MediaRouterDialogControllerImpl*
 MediaRouterDialogControllerImpl::GetOrCreateForWebContents(
     WebContents* web_contents) {
   DCHECK(web_contents);
   // This call does nothing if the controller already exists.
   MediaRouterDialogControllerImpl::CreateForWebContents(web_contents);
   return MediaRouterDialogControllerImpl::FromWebContents(web_contents);
@@ skipping 26 matching lines @@
     dialog_controller_->CloseMediaRouterDialog();
   }
 
   MediaRouterDialogControllerImpl* const dialog_controller_;
 };
 
 MediaRouterDialogControllerImpl::MediaRouterDialogControllerImpl(
     WebContents* web_contents)
     : MediaRouterDialogController(web_contents),
       media_router_dialog_pending_(false),
+      action_controller_(GetActionController(web_contents)),
       weak_ptr_factory_(this) {
+  DCHECK(action_controller_);
 }
 
 MediaRouterDialogControllerImpl::~MediaRouterDialogControllerImpl() {
+  Reset();
 }
 
 WebContents* MediaRouterDialogControllerImpl::GetMediaRouterDialog() const {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   return dialog_observer_.get() ? dialog_observer_->web_contents() : nullptr;
 }
 
 void MediaRouterDialogControllerImpl::SetMediaRouterAction(
     const base::WeakPtr<MediaRouterAction>& action) {
   action_ = action;
@@ skipping 82 matching lines @@
         media_router_dialog->GetWebUI()->GetController());
     DCHECK(media_router_ui);
     media_router_ui->SetUIInitializationTimer(dialog_creation_time);
   }
 
   media_router_dialog_pending_ = true;
 
   dialog_observer_.reset(new DialogWebContentsObserver(
       media_router_dialog, this));
 
+  // The |action_controller_| must be notified after |action_| to avoid a UI

[msw, 2016/11/04 00:07:16]

nit: Maybe override OnDialogShown in the impl to call the action first, then the
base class function? ditto for OnDialogHidden?

[takumif, 2016/11/09 04:37:27]

Sorry, I don't quite understand this comment. (The action controller doesn't
keep track of all the actions, so it can't notify the action.)

[msw, 2016/11/09 20:32:33]

hmm, it's odd that the *dialog* controller tracks the actions, but the *action*
controller doesn't... I guess some of these patterns just aren't obvious to me.

+  // bug in which the drop shadow is drawn in an incorrect position.
   if (action_)
     action_->OnDialogShown();
+  action_controller_->OnDialogShown();
 }
 
 void MediaRouterDialogControllerImpl::Reset() {
+  if (IsShowingMediaRouterDialog()) {

[msw, 2016/11/04 00:07:16]

Is it possible that multiple dialogs are showing when Reset is called, and
OnDialogHidden should be called multiple times to reset the dialog count to 0?

[takumif, 2016/11/09 04:37:27]

Each MediaRouterDialogControllerImpl can have at most one dialog, so if multiple
dialogs are shown, their respective MediaRouterDialogControllerImpls will
together reset the count to 0. 

[msw, 2016/11/09 20:32:34]

Acknowledged.

+    if (action_)
+      action_->OnDialogHidden();
+    action_controller_->OnDialogHidden();
+  }
   MediaRouterDialogController::Reset();
   dialog_observer_.reset();
-  if (action_)
-    action_->OnDialogHidden();
 }
 
 void MediaRouterDialogControllerImpl::OnDialogNavigated(
     const content::LoadCommittedDetails& details) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   WebContents* media_router_dialog = GetMediaRouterDialog();
   CHECK(media_router_dialog);
   ui::PageTransition transition_type = details.entry->GetTransitionType();
   content::NavigationType nav_type = details.type;
 
@@ skipping 29 matching lines @@
       PresentationServiceDelegateImpl::FromWebContents(initiator());
   if (!create_connection_request.get()) {
     media_router_ui->InitWithDefaultMediaSource(initiator(), delegate);
   } else {
     media_router_ui->InitWithPresentationSessionRequest(
         initiator(), delegate, std::move(create_connection_request));
   }
 }
 
 }  // namespace media_router