* refactor: use base::flat_map in ElectronMenuModel
* refactor: use base::flat_map in BuildSubmenuFromModel()
* refactor: use base::flat_map in GetDialogsMap()
* refactor: use base::flat_map in DesktopCapturer
* refactor: use base::flat_map, flat_set in ElectronBrowserClient
* refactor: use base::flat_map in ProxyingURLLoaderFactory
* refactor: use base::flat_map in MapToCommonId()
* refactor: use base::flat_map for g_map_id
* refactor: use base::flat_map for ViewsDelegate::AppbarAutohideEdgeMap
* refactor: use base::flat_map for App::app_metrics_
* refactor: use base::flat_map for PowerSaveBlocker::wake_lock_types_
* refactor: use base::flat_map for NativeImage::hicons_
* refactor: use base::flat_map for MenuViews::menu_runners_
* refactor: use base::flat_map for WebViewManager::web_contents_embedder_map_
* refactor: use base::flat_map for InspectableWebContents::extensions_api_
* refactor: use base::flat_set for libnotify GetServerCapabilities()
* refactor: use base::flat_set for InspectableWebContents::loaders_
* refactor: use base::flat_set for ElectronRendererClient::environments_
refactor: use base::flat_set for ElectronRendererClient::injected_frames_
* refactor: use base::flat_set for WebWorkerObserver::environments_
* refactor: use base::Contains() in KeyWeakMap::Has()
* refactor: use base::Contains() in WebRequest::RequestFilter::MatchesType()
* refactor: use base::Contains() in BaseWindow::AddBrowserView()
* refactor: use base::Contains() in DeepFreeze()
* refactor: use base::Contains() in Clipboard::Read()
* Revert "refactor: use base::Contains() in BaseWindow::AddBrowserView()"
This reverts commit 60152359d3978451ebdd7c8eed602c2fb8a9cafa.
* refactor: use base::Contains() in BaseWindow::AddBrowserView()
* refactor: use base::Contains() in IsDevToolsFileSystemAdded()
* refactor: use base::Contains() in MessagePort::DisentanglePorts()
* refactor: use base::Contains() in PowerSaveBlocker::IsStarted()
* refactor: use base::Contains() in SpellCheckClient::OnSpellCheckDone()
* refactor: use base::Contains() in ShowTaskDialogWstr()
* refactor: use base::Contains() in PrintViewManagerElectron::ScriptedPrint()
* refactor: use base::Contains() in PrintViewManagerElectron::DidGetPrintedPagesCount()
* refactor: use base::Contains() in NativeWindow::AddDraggableRegionProvider()
* refactor: use base::Contains() in ElectronBindings::ActivateUVLoop()
* refactor: use base::Contains() in NativeWindowViews::IsVisibleOnAllWorkspaces()
* refactor: use base::Contains() in HidChooserController::OnDeviceAdded()
* refactor: use base::Contains() in ElectronSandboxedRendererClient::WillReleaseScriptContext()
* refactor: use base::Contains() in ElectronRendererClient::WillDestroyWorkerContextOnWorkerThread()
* refactor: use base::Contains() in GlobalShortcut::OnKeyPressed()
