Add MemoryCoordinator

components/memory_coordinator/child/child_memory_coordinator_impl.cc

 // 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.
 
 #include "components/memory_coordinator/child/child_memory_coordinator_impl.h"
 
 namespace memory_coordinator {
 
+// static
+void ChildMemoryCoordinatorImpl::Create(
+    mojo::InterfaceRequest<mojom::ChildMemoryCoordinator> request) {
+  new ChildMemoryCoordinatorImpl(std::move(request), new ClientList);
+}
+
 ChildMemoryCoordinatorImpl::ChildMemoryCoordinatorImpl(
       mojo::InterfaceRequest<mojom::ChildMemoryCoordinator> request,
       scoped_refptr<ClientList> clients)
     : binding_(this, std::move(request)),
-      clients_(clients) {}
+      clients_(clients) {
+  // TODO(bashi): Add clients (e.g. skia).

[chrisha, 2016/06/27 20:35:30]

Wouldn't it make more sense for clients to add themselves? ie. via a mechanism
in MemoryCoordinatorClient constructor? (Something more akin to
MemoryPressureListener's mechanism?)

[bashi, 2016/06/27 22:40:23]

It was my first attempt. MemoryPressureListener uses a singleton to add/remove
listeners. On the other hand ChildMemoryCoordinator is a mojo interface impl and
I couldn't figure how to access it without InterfaceRequest.

+}
 
 ChildMemoryCoordinatorImpl::~ChildMemoryCoordinatorImpl() {}
 
 void ChildMemoryCoordinatorImpl::OnStateChange(mojom::MemoryState state) {
+  state_ = state;
   clients_->Notify(FROM_HERE, &MemoryCoordinatorClient::OnMemoryStateChange,
                    state);
 }
 
+void ChildMemoryCoordinatorImpl::GetCurrentState(

[chrisha, 2016/06/27 20:35:30]

Do we need this call? The state is centrally imposed from the coordinator in the
browser. It shouldn't need to query the individual child process for its memory
state.

[bashi, 2016/06/27 22:40:23]

This is for testing. Without it it's hard to make CL smaller. We may want to
rename it as GetCurrentStateForTesting().

+    const GetCurrentStateCallback& callback) {
+  callback.Run(state_);
+}
+
 }  // namespace memory_coordinator