Add GetWakeLockWithoutContext() in WakeLockContextProvider mojo interface.

device/wake_lock/wake_lock_context_provider.cc

Index: device/wake_lock/wake_lock_context_provider.cc
diff --git a/device/wake_lock/wake_lock_context_provider.cc b/device/wake_lock/wake_lock_context_provider.cc
index f7d7705a8f0d4e31726f11adc924dbce4a0100e8..62fdede8b85fbf86d7c9a4eca5bdb8709ae865ec 100644
--- a/device/wake_lock/wake_lock_context_provider.cc
+++ b/device/wake_lock/wake_lock_context_provider.cc
@@ -37,4 +37,12 @@ void WakeLockContextProvider::GetWakeLockContextForID(
       std::move(request));
 }
 
+void WakeLockContextProvider::GetUnassociatedWakeLockContext(
+    mojo::InterfaceRequest<mojom::WakeLockContext> request) {
+  mojo::MakeStrongBinding(base::MakeUnique<WakeLockServiceContext>(
+                              WakeLockServiceContext::WakeLockInvalidContextId,
+                              file_task_runner_, native_view_getter_),
+                          std::move(request));
+}
+
 }  // namespace device