MPRIS: Set CanControl to true

In a refactor, we had accidentally changed the "CanControl" MPRIS
property to be false instead of true. This CL changes it back.

Bug: 1056629
Change-Id: Ie072f735bf10510f2c231d7d1f33d13f95101c80
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2078974Reviewed-by: Thomas Anderson <thomasanderson@chromium.org>
Commit-Queue: Tommy Steimel <steimel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#745530}

components/system_media_controls/linux/system_media_controls_linux.cc

@@ -185,7 +185,7 @@ void SystemMediaControlsLinux::InitializeProperties() {
   set_player_property("CanPlay", DbusBoolean(false));
   set_player_property("CanPause", DbusBoolean(false));
   set_player_property("CanSeek", DbusBoolean(false));
-  set_player_property("CanControl", DbusBoolean(false));
+  set_player_property("CanControl", DbusBoolean(true));
 }
 
 void SystemMediaControlsLinux::InitializeDbusInterface() {