Move services/shell to services/service_manager

Moving the symbols to the service_manager namespace will
happen in a follow-up CL.

Copied from https://codereview.chromium.org/2419723002 because
rietveld is choking on that one.

BUG=None
NOPRESUBMIT=true
[email protected]
[email protected]
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2419063003
Cr-Commit-Position: refs/heads/master@{#425565}
diff --git a/content/gpu/BUILD.gn b/content/gpu/BUILD.gn
index bb98524..a4379e42 100644
--- a/content/gpu/BUILD.gn
+++ b/content/gpu/BUILD.gn
@@ -61,8 +61,8 @@
     "//ipc",
     "//media/gpu",
     "//media/gpu/ipc/service",
-    "//services/shell/public/cpp",
-    "//services/shell/public/interfaces",
+    "//services/service_manager/public/cpp",
+    "//services/service_manager/public/interfaces",
     "//skia",
     "//ui/events/ipc",
     "//ui/gfx/ipc",