Clean up HID backend and API.

chrome/browser/extensions/api/hid/hid_device_manager.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.o
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/extensions/api/hid/hid_device_manager.h"
+
+#include "base/lazy_instance.h"
+#include "device/hid/hid_service.h"
+
+using device::HidService;
+
+namespace extensions {
+
+static base::LazyInstance<ProfileKeyedAPIFactory<HidDeviceManager> > g_factory =

[Mark Mentovai, 2014/02/24 20:23:36]

This is only used by GetFactoryInstance, you can move it into that function.

[Ken Rockot(use gerrit already), 2014/02/25 21:30:01]

Done.

+    LAZY_INSTANCE_INITIALIZER;
+
+HidDeviceManager::HidDeviceManager(Profile* profile) : next_resource_id_(0) {}
+
+HidDeviceManager::~HidDeviceManager() {}
+
+// static
+ProfileKeyedAPIFactory<HidDeviceManager>*
+HidDeviceManager::GetFactoryInstance() {
+  return &g_factory.Get();
+}
+
+scoped_ptr<base::ListValue> HidDeviceManager::GetApiDevices(
+    uint16_t vendor_id,
+    uint16_t product_id) {
+  UpdateDevices();
+
+  HidService* hid_service = HidService::GetInstance();
+  DCHECK(hid_service);
+  base::ListValue* api_devices = new base::ListValue();
+  for (ResourceIdToDeviceIdMap::const_iterator device_iter =
+           device_ids_.begin();
+       device_iter != device_ids_.end();
+       ++device_iter) {
+    int resource_id = device_iter->first;
+    device::HidDeviceId device_id = device_iter->second;
+    device::HidDeviceInfo device_info;
+    if (hid_service->GetDeviceInfo(device_id, &device_info)) {
+      if (device_info.vendor_id == vendor_id &&
+          device_info.product_id == product_id) {
+        api::hid::HidDeviceInfo api_device_info;
+        api_device_info.device_id = resource_id;
+        api_device_info.vendor_id = device_info.vendor_id;
+        api_device_info.product_id = device_info.product_id;
+        api_devices->Append(api_device_info.ToValue().release());
+      }
+    }
+  }
+  return scoped_ptr<base::ListValue>(api_devices);
+}
+
+bool HidDeviceManager::GetDeviceInfo(int resource_id,
+                                     device::HidDeviceInfo* device_info) {
+  UpdateDevices();
+  HidService* hid_service = HidService::GetInstance();
+  DCHECK(hid_service);
+
+  ResourceIdToDeviceIdMap::const_iterator device_iter =
+      device_ids_.find(resource_id);
+  if (device_iter == device_ids_.end())
+    return false;
+
+  return hid_service->GetDeviceInfo(device_iter->second, device_info);
+}
+
+void HidDeviceManager::UpdateDevices() {
+  thread_checker_.CalledOnValidThread();
+  HidService* hid_service = HidService::GetInstance();
+  DCHECK(hid_service);
+
+  std::vector<device::HidDeviceInfo> devices;
+  hid_service->GetDevices(&devices);
+
+  // Build an updated bidi mapping between resource ID and underlying device ID.
+  DeviceIdToResourceIdMap new_resource_ids;
+  ResourceIdToDeviceIdMap new_device_ids;
+  for (std::vector<device::HidDeviceInfo>::const_iterator iter =
+           devices.begin();
+       iter != devices.end();
+       ++iter) {
+    const device::HidDeviceInfo& device_info = *iter;
+    DeviceIdToResourceIdMap::iterator resource_iter =
+        resource_ids_.find(device_info.device_id);
+    int new_id = 0;

[Mark Mentovai, 2014/02/24 20:23:36]

No need to initialize.

+    if (resource_iter != resource_ids_.end())
+      new_id = resource_iter->second;
+    else
+      new_id = next_resource_id_++;

[Mark Mentovai, 2014/02/24 20:23:36]

Extreme paranoia, but before you hit this line, maybe DCHECK that
next_resource_id_ isn’t std::numeric_limits<int>::min().

[Ken Rockot(use gerrit already), 2014/02/25 21:30:01]

Done.

+    new_resource_ids[device_info.device_id] = new_id;
+    new_device_ids[new_id] = device_info.device_id;
+  }
+
+  device_ids_ = new_device_ids;

[Mark Mentovai, 2014/02/24 20:23:36]

This is a copy followed by an immediate discard of the source. How about a .swap
instead? Same on the next line.

[Ken Rockot(use gerrit already), 2014/02/25 21:30:01]

Done.

+  resource_ids_ = new_resource_ids;
+}
+
+}  // namespace extensions