Delete stashed message port implementation from content.

It's not entirely clear what the future of navigator.connect is, but stashed
ports is definitely not it.

[1/3] https://codereview.chromium.org/1248003003, deleting most of the blink side of the code
[2/3] This patch, deletes the content side
[3/3] https://codereview.chromium.org/1248893003, deletes the rest of the blink code

BUG=483108

Review URL: https://codereview.chromium.org/1248763005

Cr-Commit-Position: refs/heads/master@{#339919}
diff --git a/content/browser/storage_partition_impl.h b/content/browser/storage_partition_impl.h
index 25000450..0aeb104 100644
--- a/content/browser/storage_partition_impl.h
+++ b/content/browser/storage_partition_impl.h
@@ -18,7 +18,6 @@
 #include "content/browser/navigator_connect/navigator_connect_context_impl.h"
 #include "content/browser/notifications/platform_notification_context_impl.h"
 #include "content/browser/service_worker/service_worker_context_wrapper.h"
-#include "content/browser/service_worker/stashed_port_manager.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/storage_partition.h"
 #include "storage/browser/quota/special_storage_policy.h"
@@ -58,7 +57,6 @@
   NavigatorConnectContextImpl* GetNavigatorConnectContext() override;
   PlatformNotificationContextImpl* GetPlatformNotificationContext() override;
   BackgroundSyncContextImpl* GetBackgroundSyncContext();
-  StashedPortManager* GetStashedPortManager();
 
   void ClearDataForOrigin(uint32 remove_mask,
                           uint32 quota_storage_remove_mask,
@@ -144,8 +142,7 @@
       HostZoomLevelContext* host_zoom_level_context,
       NavigatorConnectContextImpl* navigator_connect_context,
       PlatformNotificationContextImpl* platform_notification_context,
-      BackgroundSyncContextImpl* background_sync_context,
-      StashedPortManager* stashed_port_manager);
+      BackgroundSyncContextImpl* background_sync_context);
 
   void ClearDataImpl(uint32 remove_mask,
                      uint32 quota_storage_remove_mask,
@@ -191,7 +188,6 @@
   scoped_refptr<NavigatorConnectContextImpl> navigator_connect_context_;
   scoped_refptr<PlatformNotificationContextImpl> platform_notification_context_;
   scoped_refptr<BackgroundSyncContextImpl> background_sync_context_;
-  scoped_refptr<StashedPortManager> stashed_port_manager_;
 
   // Raw pointer that should always be valid. The BrowserContext owns the
   // StoragePartitionImplMap which then owns StoragePartitionImpl. When the