Refactored gamepad polling to support dynamic sources

device/gamepad/gamepad_data_fetcher_manager.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 "device/gamepad/gamepad_data_fetcher_manager.h"
+
+#include "device/gamepad/gamepad_data_fetcher.h"
+#include "device/gamepad/gamepad_platform_data_fetcher.h"
+
+namespace device {
+
+namespace {
+GamepadDataFetcherManager* g_gamepad_data_fetcher_manager = 0;
+}
+
+GamepadDataFetcherManager::GamepadDataFetcherManager() : provider_(nullptr) {}
+
+GamepadDataFetcherManager::~GamepadDataFetcherManager() {}
+
+GamepadDataFetcherManager* GamepadDataFetcherManager::GetInstance() {
+  if (!g_gamepad_data_fetcher_manager) {
+    g_gamepad_data_fetcher_manager = new GamepadDataFetcherManager;
+
+    // Add platform specific data fetchers
+    AddGamepadPlatformDataFetchers(g_gamepad_data_fetcher_manager);
+  }
+  return g_gamepad_data_fetcher_manager;
+}
+
+void GamepadDataFetcherManager::AddFactory(GamepadDataFetcherFactory* factory) {
+  factories_.push_back(factory);
+  if (provider_) {
+    provider_->AddGamepadDataFetcher(factory->CreateDataFetcher());
+  }
+}
+
+void GamepadDataFetcherManager::RemoveSourceFactory(GamepadSource source) {
+  if (provider_)
+    provider_->RemoveSourceGamepadDataFetcher(source);
+
+  for (FactoryVector::iterator it = factories_.begin(); it != factories_.end();
+       ++it) {
+    if ((*it)->source() == source) {
+      delete (*it);
+      factories_.erase(it);
+    }
+  }
+}
+
+void GamepadDataFetcherManager::InitializeProvider(GamepadProvider* provider) {
+  DCHECK(!provider_);
+
+  provider_ = provider;
+  for (const auto& it : factories_) {
+    provider_->AddGamepadDataFetcher(it->CreateDataFetcher());
+  }
+}
+
+void GamepadDataFetcherManager::ClearProvider() {
+  provider_ = nullptr;
+}
+
+}  // namespace device