Refactor GvrDelegate ownership into GvrDelegateProvider and fix more threading violations.

chrome/browser/android/vr_shell/BUILD.gn

 # Copyright 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/android/rules.gni")
 import("//chrome/common/features.gni")
 import("//testing/test.gni")
 
 assert(enable_vr_shell || enable_webvr)
 
@@ skipping 50 matching lines @@
     }
 
     deps = [
       ":vr_shell_jni_headers",
       "//base",
       "//cc",
       "//components/rappor",
       "//components/security_state/core",
       "//content/public/browser",
       "//content/public/common",
+      "//device/gamepad",
       "//device/vr",
       "//ui/android",
       "//ui/base",
       "//ui/display",
       "//ui/gl",
       "//ui/gl/init",
     ]
 
     libs = [
       "//third_party/gvr-android-sdk/libgvr_shim_static_${current_cpu}.a",
@@ skipping 22 matching lines @@
       ":vr_common",
       "//base/test:run_all_unittests",
       "//base/test:test_support",
       "//chrome/browser",
       "//testing/gtest",
       "//third_party/WebKit/public:blink",
       "//ui/gfx/geometry",
     ]
   }
 }