Introduce chrome.displaySource API

extensions/browser/api/display_source/display_source_event_router.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 "extensions/browser/api/display_source/display_source_event_router.h"
+
+#include "content/public/browser/browser_context.h"
+#include "extensions/browser/api/display_source/display_source_api.h"
+#include "extensions/browser/api/display_source/display_source_connection_delegate_factory.h"
+#include "extensions/common/api/display_source.h"
+
+namespace extensions {
+
+DisplaySourceEventRouter::DisplaySourceEventRouter(
+    content::BrowserContext* browser_context)
+    : browser_context_(browser_context), listening_(false) {
+  EventRouter* event_router = EventRouter::Get(browser_context_);
+  if (!event_router)
+    return;
+  event_router->RegisterObserver(
+      this, api::display_source::OnSinksUpdated::kEventName);
+}
+
+DisplaySourceEventRouter::~DisplaySourceEventRouter() {
+  DCHECK(!listening_);
+}
+
+void DisplaySourceEventRouter::Shutdown() {
+  EventRouter* event_router = EventRouter::Get(browser_context_);
+  if (event_router)
+    event_router->UnregisterObserver(this);
+
+  if (!listening_)
+    return;
+  listening_ = false;
+  DisplaySourceConnectionDelegate* delegate =
+      DisplaySourceConnectionDelegateFactory::GetForBrowserContext(
+          browser_context_);
+  if (delegate)
+    delegate->RemoveObserver(this);
+}
+
+void DisplaySourceEventRouter::OnListenerAdded(
+    const EventListenerInfo& details) {
+  StartOrStopListeningForSinksChanges();
+}
+
+void DisplaySourceEventRouter::OnListenerRemoved(
+    const EventListenerInfo& details) {
+  StartOrStopListeningForSinksChanges();
+}
+
+void DisplaySourceEventRouter::StartOrStopListeningForSinksChanges() {
+  EventRouter* event_router = EventRouter::Get(browser_context_);
+  if (!event_router)
+    return;
+
+  bool should_listen = event_router->HasEventListener(
+      api::display_source::OnSinksUpdated::kEventName);
+  if (should_listen && !listening_) {
+    DisplaySourceConnectionDelegate* delegate =
+        DisplaySourceConnectionDelegateFactory::GetForBrowserContext(
+            browser_context_);
+    if (delegate) {
+      delegate->AddObserver(this);
+      delegate->StartWatchingSinks();
+    }
+  }
+  if (!should_listen && listening_) {
+    DisplaySourceConnectionDelegate* delegate =
+        DisplaySourceConnectionDelegateFactory::GetForBrowserContext(
+            browser_context_);
+    if (delegate) {
+      delegate->RemoveObserver(this);
+      delegate->StopWatchingSinks();
+    }
+  }
+
+  listening_ = should_listen;
+}
+
+void DisplaySourceEventRouter::OnSinksUpdated(
+    const DisplaySourceSinkInfoList& sinks) {
+  EventRouter* event_router = EventRouter::Get(browser_context_);
+  if (!event_router)
+    return;
+  scoped_ptr<base::ListValue> args(
+      api::display_source::OnSinksUpdated::Create(sinks));
+  scoped_ptr<Event> sinks_updated_event(
+      new Event(events::DISPLAY_SOURCE_ON_SINKS_UPDATED,
+                api::display_source::OnSinksUpdated::kEventName, args.Pass()));
+  event_router->BroadcastEvent(sinks_updated_event.Pass());
+}
+
+DisplaySourceEventRouter* DisplaySourceEventRouter::Create(
+    content::BrowserContext* browser_context) {
+  return new DisplaySourceEventRouter(browser_context);
+}
+
+}  // namespace extensions