[Sync] Fix namespaces for the sync_sessions component.

Things within a component should have a namespace that matches its name.

BUG=646685
TBR=jam

Review-Url: https://codereview.chromium.org/2343463003
Cr-Commit-Position: refs/heads/master@{#418878}
diff --git a/chrome/browser/BUILD.gn b/chrome/browser/BUILD.gn
index 0a499b2..e4f9f277 100644
--- a/chrome/browser/BUILD.gn
+++ b/chrome/browser/BUILD.gn
@@ -3298,8 +3298,8 @@
       "sync/glue/synced_window_delegates_getter_android.h",
       "sync/profile_sync_service_android.cc",
       "sync/profile_sync_service_android.h",
-      "sync/sync_sessions_metrics_android.cc",
-      "sync/sync_sessions_metrics_android.h",
+      "sync/sessions/sync_sessions_metrics_android.cc",
+      "sync/sessions/sync_sessions_metrics_android.h",
     ]
     deps += [
       ":client_discourse_context_proto",