WindowManagerClient::AddAccelerator() should take an array

ash/mus/accelerators/accelerator_controller_registrar.cc

Index: ash/mus/accelerators/accelerator_controller_registrar.cc
diff --git a/ash/mus/accelerators/accelerator_controller_registrar.cc b/ash/mus/accelerators/accelerator_controller_registrar.cc
index 79d7ea794ccaf9247c1c76c5187e4a1abfe8b742..c6ba5d827adb7313ff12130d509c595b907e9782 100644
--- a/ash/mus/accelerators/accelerator_controller_registrar.cc
+++ b/ash/mus/accelerators/accelerator_controller_registrar.cc
@@ -13,6 +13,7 @@
 #include "ash/mus/bridge/wm_window_mus.h"
 #include "ash/mus/window_manager.h"
 #include "base/logging.h"
+#include "services/ui/common/accelerator_transport_util.h"
 #include "services/ui/common/event_matcher_util.h"
 #include "services/ui/public/cpp/window_manager_delegate.h"
 #include "services/ui/public/cpp/window_tree_client.h"
@@ -126,12 +127,23 @@ void AcceleratorControllerRegistrar::OnAcceleratorRegistered(
   post_event_matcher->accelerator_phase =
       ui::mojom::AcceleratorPhase::POST_TARGET;
 
-  window_manager_->window_manager_client()->AddAccelerator(
-      ComputeAcceleratorId(id_namespace_, ids.pre_id), std::move(event_matcher),
-      base::Bind(OnAcceleratorAdded, accelerator));
-  window_manager_->window_manager_client()->AddAccelerator(
-      ComputeAcceleratorId(id_namespace_, ids.post_id),
-      std::move(post_event_matcher),
+  std::vector<ui::mojom::AcceleratorTransportPtr> pre_accelerators;
+  pre_accelerators =
+      AddAcceleratorHelper(std::move(pre_accelerators),

[mfomitchev, 2016/11/29 01:55:45]

You are never passing a non-empty vector to AddAcceleratorHelper. So perhaps
just make it take id and matcher and return an
std::vector<ui::mojom::AcceleratorTransportPtr>?

If do need to add accelerators to non-empty vector: 
Make AddAcceleratorHelper take a pointer to
std::vector<ui::mojom::AcceleratorTransportPtr> and return nothing and make it
modify the provided std::vector<ui::mojom::AcceleratorTransportPtr>. This way we
don't have to do std::move twice. I find doing std::move a little confusing it
terms of semantics, since we are not actually transferring the ownership.

[thanhph, 2016/11/29 16:50:17]

Done, thanks! I use the first approach since the later didn't work. When I use
std::move to pass std::vector argument to the void 
AddAcceleratorHelper(std::vector<ui::mojom::AcceleratorTransportPtr>, uint32_t
id, ui::mojom::EventMatcherPtr event_matcher), the pointer to std::vector is
gone thus I can't reuse the std::vector on the return function.

+                           ComputeAcceleratorId(id_namespace_, ids.pre_id),
+                           std::move(event_matcher));
+
+  window_manager_->window_manager_client()->AddAccelerators(
+      std::move(pre_accelerators), base::Bind(OnAcceleratorAdded, accelerator));
+
+  std::vector<ui::mojom::AcceleratorTransportPtr> post_accelerators;
+  post_accelerators =
+      AddAcceleratorHelper(std::move(post_accelerators),
+                           ComputeAcceleratorId(id_namespace_, ids.post_id),
+                           std::move(post_event_matcher));
+
+  window_manager_->window_manager_client()->AddAccelerators(
+      std::move(post_accelerators),
       base::Bind(OnAcceleratorAdded, accelerator));
 }