Remove PlatformClientAuth interface from upstream.

chromecast/browser/cast_browser_main_parts.cc

Index: chromecast/browser/cast_browser_main_parts.cc
diff --git a/chromecast/browser/cast_browser_main_parts.cc b/chromecast/browser/cast_browser_main_parts.cc
index d098b063e22e7e5eed15cac013c518ba6368119a..1fab3cfd1734e15f4c053d2bce6411cf6e52a9b7 100644
--- a/chromecast/browser/cast_browser_main_parts.cc
+++ b/chromecast/browser/cast_browser_main_parts.cc
@@ -40,7 +40,6 @@
 #include "chromecast/browser/pref_service_helper.h"
 #include "chromecast/browser/url_request_context_factory.h"
 #include "chromecast/chromecast_features.h"
-#include "chromecast/common/platform_client_auth.h"
 #include "chromecast/media/base/key_systems_common.h"
 #include "chromecast/media/base/media_resource_tracker.h"
 #include "chromecast/media/base/video_plane_controller.h"
@@ -449,9 +448,6 @@ void CastBrowserMainParts::PreMainMessageLoopRun() {
               cast_browser_process_->browser_context())->
                   GetURLRequestContext()));
 
-  if (!PlatformClientAuth::Initialize())
-    LOG(ERROR) << "PlatformClientAuth::Initialize failed.";
-
   cast_browser_process_->SetRemoteDebuggingServer(
       base::MakeUnique<RemoteDebuggingServer>(
           cast_browser_process_->browser_client()