[Media Router] Conditionally enable mDNS on Windows.

chrome/browser/media/router/media_router_mojo_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/media/router/media_router_mojo_impl.h"
 
 #include <stddef.h>
 #include <utility>
 
 #include "base/bind.h"
 #include "base/guid.h"
 #include "base/logging.h"
 #include "base/memory/scoped_vector.h"
 #include "base/observer_list.h"
 #include "base/stl_util.h"
 #include "base/strings/stringprintf.h"
+#include "build/build_config.h"
 #include "chrome/browser/media/router/issues_observer.h"
+#include "chrome/browser/media/router/media_route_provider_util_win.h"
 #include "chrome/browser/media/router/media_router_factory.h"
 #include "chrome/browser/media/router/media_router_metrics.h"
 #include "chrome/browser/media/router/media_router_type_converters.h"
 #include "chrome/browser/media/router/media_routes_observer.h"
 #include "chrome/browser/media/router/media_sinks_observer.h"
 #include "chrome/browser/media/router/presentation_session_messages_observer.h"
 #include "chrome/browser/sessions/session_tab_helper.h"
 #include "extensions/browser/process_manager.h"
 
 #define DVLOG_WITH_INSTANCE(level) \
@@ skipping 46 matching lines @@
 MediaRouterMojoImpl::MediaSinksQuery::~MediaSinksQuery() = default;
 
 MediaRouterMojoImpl::MediaRouterMojoImpl(
     extensions::EventPageTracker* event_page_tracker)
     : event_page_tracker_(event_page_tracker),
       instance_id_(base::GenerateGUID()),
       availability_(interfaces::MediaRouter::SinkAvailability::UNAVAILABLE),
       current_wake_reason_(MediaRouteProviderWakeReason::TOTAL_COUNT),
       weak_factory_(this) {
   DCHECK(event_page_tracker_);
+#if defined(OS_WIN)
+  should_enable_mdns_discovery_ = false;
+  CanFirewallUseLocalPorts(
+      base::Bind(&MediaRouterMojoImpl::EnableMdnsFromFirewallCheck,
+                 base::Unretained(this)));
+#endif
 }
 
 MediaRouterMojoImpl::~MediaRouterMojoImpl() {
   DCHECK(thread_checker_.CalledOnValidThread());
 }
 
 // static
 void MediaRouterMojoImpl::BindToRequest(
     const extensions::Extension* extension,
     content::BrowserContext* context,
@@ skipping 56 matching lines @@
     AttemptWakeEventPage();
     return;
   }
 
   media_route_provider_ = std::move(media_route_provider_ptr);
   media_route_provider_.set_connection_error_handler(base::Bind(
       &MediaRouterMojoImpl::OnConnectionError, base::Unretained(this)));
   callback.Run(instance_id_);
   ExecutePendingRequests();
   wakeup_attempt_count_ = 0;
+#if defined(OS_WIN)
+  if (should_enable_mdns_discovery_) {
+    media_route_provider_->EnableMdnsDiscovery();
+  }
+#endif
 }
 
 void MediaRouterMojoImpl::OnIssue(const interfaces::IssuePtr issue) {
   DCHECK(thread_checker_.CalledOnValidThread());
   DVLOG_WITH_INSTANCE(1) << "OnIssue " << issue->title;
   const Issue& issue_converted = issue.To<Issue>();
   issue_manager_.AddIssue(issue_converted);
 }
 
 void MediaRouterMojoImpl::OnSinksReceived(
@@ skipping 225 matching lines @@
 void MediaRouterMojoImpl::AddIssue(const Issue& issue) {
   DCHECK(thread_checker_.CalledOnValidThread());
   issue_manager_.AddIssue(issue);
 }
 
 void MediaRouterMojoImpl::ClearIssue(const Issue::Id& issue_id) {
   DCHECK(thread_checker_.CalledOnValidThread());
   issue_manager_.ClearIssue(issue_id);
 }
 
+bool MediaRouterMojoImpl::should_enable_mdns_discovery() const {
+  return should_enable_mdns_discovery_;
+}
+
+void MediaRouterMojoImpl::EnsureMdnsDiscoveryEnabled() {
+  if (media_route_provider_) {
+    media_route_provider_->EnableMdnsDiscovery();

[imcheng, 2016/03/25 06:26:30]

So when this is called, it is possible that the MR extension is not loaded (with
exception being RegisterMediaRouteProvider). You will need to queue a task and
wake up the extension. See
RegisterMediaSinksObserver for example.

[btolsch, 2016/03/25 18:57:04]

Done.

+  }
+  should_enable_mdns_discovery_ = true;
+}
+
 bool MediaRouterMojoImpl::RegisterMediaSinksObserver(
     MediaSinksObserver* observer) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   // Create an observer list for the media source and add |observer|
   // to it. Fail if |observer| is already registered.
   const std::string& source_id = observer->source().id();
   auto* sinks_query = sinks_queries_.get(source_id);
   bool new_query = false;
   if (!sinks_query) {
@@ skipping 508 matching lines @@
   DCHECK(reason != MediaRouteProviderWakeReason::TOTAL_COUNT);
   if (current_wake_reason_ == MediaRouteProviderWakeReason::TOTAL_COUNT)
     current_wake_reason_ = reason;
 }
 
 void MediaRouterMojoImpl::ClearWakeReason() {
   DCHECK(current_wake_reason_ != MediaRouteProviderWakeReason::TOTAL_COUNT);
   current_wake_reason_ = MediaRouteProviderWakeReason::TOTAL_COUNT;
 }
 
+void MediaRouterMojoImpl::EnableMdnsFromFirewallCheck(
+    bool firewall_can_use_local_ports) {
+  if (firewall_can_use_local_ports) {
+    EnsureMdnsDiscoveryEnabled();
+  }
+}
+
 }  // namespace media_router