chromeos: get EasyUnlockPrivateApiTests working with mus

Creating BluezDBusManager is unnecessary for --mus, as
WindowManagerService (in ash) takes care of it.

BUG=776514
TEST=test only change

Change-Id: Ie3b7e39a507a9263779ce8f1045141e51d81192f
Reviewed-on: https://chromium-review.googlesource.com/823526Reviewed-by: James Cook <jamescook@chromium.org>
Commit-Queue: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#523697}

chrome/browser/extensions/api/easy_unlock_private/easy_unlock_private_api_chromeos_unittest.cc

@@ -33,6 +33,7 @@
 #include "extensions/browser/test_event_router.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/cros_system_api/dbus/service_constants.h"
+#include "ui/aura/env.h"
 
 namespace {
 
@@ -130,9 +131,11 @@ class EasyUnlockPrivateApiTest : public extensions::ExtensionApiUnittest {
         proximity_auth::switches::kDisableBluetoothLowEnergyDiscovery);
 
     chromeos::DBusThreadManager::Initialize();
+    if (aura::Env::GetInstance()->mode() == aura::Env::Mode::LOCAL) {
       bluez::BluezDBusManager::Initialize(
           chromeos::DBusThreadManager::Get()->GetSystemBus(),
           chromeos::DBusThreadManager::Get()->IsUsingFakes());
+    }
     client_ = chromeos::DBusThreadManager::Get()->GetEasyUnlockClient();
 
     extensions::ExtensionApiUnittest::SetUp();
@@ -141,6 +144,7 @@ class EasyUnlockPrivateApiTest : public extensions::ExtensionApiUnittest {
   void TearDown() override {
     extensions::ExtensionApiUnittest::TearDown();
 
+    if (aura::Env::GetInstance()->mode() == aura::Env::Mode::LOCAL)
       bluez::BluezDBusManager::Shutdown();
     chromeos::DBusThreadManager::Shutdown();
   }