Convert CastTransportHostFilter to be client of wake lock service.

chrome/browser/media/cast_transport_host_filter.h

Index: chrome/browser/media/cast_transport_host_filter.h
diff --git a/chrome/browser/media/cast_transport_host_filter.h b/chrome/browser/media/cast_transport_host_filter.h
index 82aac94c4c3fb8c358d6511376d135d0fe05db93..29be61c18e4bc9959a60db2e5907e2806e66205f 100644
--- a/chrome/browser/media/cast_transport_host_filter.h
+++ b/chrome/browser/media/cast_transport_host_filter.h
@@ -15,15 +15,13 @@
 #include "base/time/default_tick_clock.h"
 #include "chrome/browser/media/cast_remoting_sender.h"
 #include "content/public/browser/browser_message_filter.h"
+#include "content/public/common/service_manager_connection.h"

[Ken Rockot(use gerrit already), 2017/05/31 11:50:49]

Please move this include to the cc file, ServiceManagerConnection's definition
is never used by this header

[ke.he, 2017/05/31 12:45:10]

Done.

+#include "device/wake_lock/public/interfaces/wake_lock_service.mojom.h"
 #include "media/cast/cast_sender.h"
 #include "media/cast/logging/logging_defines.h"
 #include "media/cast/net/cast_transport.h"
 #include "media/cast/net/udp_transport.h"
 
-namespace device {
-class PowerSaveBlocker;
-}  // namespace device
-
 namespace cast {
 
 class CastTransportHostFilter : public content::BrowserMessageFilter {
@@ -33,6 +31,9 @@ class CastTransportHostFilter : public content::BrowserMessageFilter {
  private:
   ~CastTransportHostFilter() override;
 
+  static void BindConnectorRequest(

[Ken Rockot(use gerrit already), 2017/05/31 11:50:49]

Please remove this from the class. It can be defined entirely within an
anonymous namespace in the cc

[ke.he, 2017/05/31 12:45:10]

Done.

+      service_manager::mojom::ConnectorRequest connector_request);
+
   // Status callback to create UdpTransport.
   void OnStatusChanged(int32_t channel_id,
                        media::cast::CastTransportStatus status);
@@ -93,15 +94,19 @@ class CastTransportHostFilter : public content::BrowserMessageFilter {
       int32_t channel_id,
       const std::vector<media::cast::FrameEvent>& events);
 
+  device::mojom::WakeLockService* GetWakeLockService();
+
   IDMap<std::unique_ptr<media::cast::CastTransport>> id_map_;
 
   // Clock used by Cast transport.
   base::DefaultTickClock clock_;
 
-  // While |id_map_| is non-empty, hold an instance of
-  // device::PowerSaveBlocker.  This prevents Chrome from being suspended while
-  // remoting content.
-  std::unique_ptr<device::PowerSaveBlocker> power_save_blocker_;
+  // While |id_map_| is non-empty, request the WakeLockService to hold a wake

[Ken Rockot(use gerrit already), 2017/05/31 11:50:49]

How about "While |id_map_| is is non-empty, we use |wake_lock_| to request and
hold a wake lock. If any wake lock is held upon destruction, it's implicitly
canceled when this object is destroyed."

IMHO no need to explain the implementation details of Mojo bindings or the
service here. It may be best to document the service behavior in the mojom
rather than at the site of each client's usage.

[ke.he, 2017/05/31 12:45:10]

Done.

+  // lock. This prevents Chrome from being suspended while remoting content.
+  // Destruction of wake_lock_service_ will trigger
+  // WakeLockServicImpl::OnConnectionError on the service side, so there is no
+  // need to call CancelWakeLock() in the destructor.
+  device::mojom::WakeLockServicePtr wake_lock_service_;

[Ken Rockot(use gerrit already), 2017/05/31 11:50:49]

super nit: can we please just call this |wake_lock_|?

I would like to someday rename WakeLockService to WakeLock, as we should rid
ourselves of the habit of calling interfaces "services"

[ke.he, 2017/05/31 12:45:10]

Done.
 
Yeah, I think we can do the rename when moving it to //services/device/, after
all clients of wakelock be converted.

 
   // This map records all active remoting senders. It uses the unique RTP
   // stream ID as the key.