Device Service: Decouple Wake Lock from //content

content/browser/wake_lock/wake_lock_context_host.cc

+// Copyright 2017 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 "content/browser/wake_lock/wake_lock_context_host.h"
+
+#include "base/atomic_sequence_num.h"
+#include "base/lazy_instance.h"
+#include "content/public/common/service_manager_connection.h"
+#include "device/wake_lock/public/interfaces/wake_lock_context_provider.mojom.h"
+#include "mojo/public/cpp/bindings/strong_binding.h"
+#include "services/device/public/interfaces/constants.mojom.h"
+#include "services/service_manager/public/cpp/connector.h"
+
+namespace content {
+
+namespace {
+
+base::StaticAtomicSequenceNumber g_unique_id;
+
+base::LazyInstance<std::map<int, WakeLockContextHost*>>::DestructorAtExit

[dcheng, 2017/03/17 06:55:25]

Does this need to be DestructorAtExit?

[blundell, 2017/03/17 12:28:21]

I cargo-culted from here:
https://cs.chromium.org/chromium/src/content/browser/browser_context.cc?dr&q=...

Changed to Leaky, as I can't think of a reason the destructor needs to run here.

+    g_id_to_context_host = LAZY_INSTANCE_INITIALIZER;
+
+WakeLockContextHost* ContextHostFromId(int id) {
+  auto it = g_id_to_context_host.Get().find(id);
+  return it != g_id_to_context_host.Get().end() ? it->second : nullptr;
+}
+
+}  // namespace
+
+WakeLockContextHost::WakeLockContextHost(WebContents* web_contents)
+    : id_(g_unique_id.GetNext()), web_contents_(web_contents) {
+  g_id_to_context_host.Get()[id_] = this;
+
+  // Connect to a WakeLockContext, associating it with |id_|.
+  if (ServiceManagerConnection::GetForProcess()) {

[dcheng, 2017/03/17 06:55:25]

Out of curiosity, why is this check needed at all?

[blundell, 2017/03/17 12:28:21]

In unittests the service manager connection is not initialized. Added a comment
to this effect.

[dcheng, 2017/03/22 10:09:55]

Out of curiosity, is there any chance to add some thing like
TestBrowserThreadBundle so that it would Just Work in tests?

(I ask this because I've been surprised by the RenderThreadImpl::current() is
null in tests behavior in the past; it just so happened that the 'null in tests'
check written into non-test code ended up masking other issues)

[blundell, 2017/03/22 13:03:40]

Filed crbug.com/704098 to track this.

+    service_manager::Connector* connector =
+        ServiceManagerConnection::GetForProcess()->GetConnector();
+    DCHECK(connector);
+    device::mojom::WakeLockContextProviderPtr context_provider;
+    connector->BindInterface(device::mojom::kServiceName,
+                             mojo::MakeRequest(&context_provider));
+    context_provider->GetContext(id_, mojo::MakeRequest(&wake_lock_context_));
+  }
+}
+
+WakeLockContextHost::~WakeLockContextHost() {
+  g_id_to_context_host.Get()[id_] = nullptr;

[dcheng, 2017/03/17 06:55:25]

Nit: erase()?

[blundell, 2017/03/17 12:28:21]

Done.

+}
+
+// static
+gfx::NativeView WakeLockContextHost::GetNativeViewForContext(int context_id) {
+  WakeLockContextHost* context_host = ContextHostFromId(context_id);
+  if (context_host)
+    return context_host->web_contents_->GetNativeView();
+  return nullptr;
+}
+
+}  // namespace content