* refactor: in FramelessView, move empty function decls to header
* refactor: in electron::api::WebContents, move empty function decls to header
* refactor: in electron::api::NativeWindow, move empty function decls to header
* refactor: in electron::OffScreenWebContentsView, move empty function decls to header
* refactor: in electron::OffScreenRenderWidgetHostView, move empty function decls to header
* refactor: in auto_updater::AutoUpdater, move empty function decls to header
* refactor: in electorn::api::FrameSubscriber, move empty function decls to header
* refactor: in electorn::api::SimpleURLLoaderWrapper, move empty function decls to header
* refactor: in electorn::InspectableWebContents, move empty function decls to header
* refactor: in electorn::OffScreenVideoConsumer, move empty function decls to header
* refactor: in electron::OffScreenWebContentsView, move empty function decls to header
* refactor: in electron::TrayIcon, move empty function decls to header
* refactor: in electron::ViewsDelegate, move empty function decls to header
* refactor: in electron::MediaCaptureDevicesDispatcher, move empty function decls to header
* refactor: in electron::UsbChooserContext::DeviceObserver, move empty function decls to header
* refactor: in electron::ProxyingWebSocket, move empty function decls to header
* refactor: in electron::Notification, move empty function decls to header
* refactor: in electron::PlatformNotificationService, move empty function decls to header
* Revert "refactor: in electron::PlatformNotificationService, move empty function decls to header"
This reverts commit 9103750d03b9ba1ceccba43d11dfdc2404ff6191.
* refactor: in electron::ElectronPDFDocumentHelperClient, move empty function decls to header
* refactor: in electron::api::SpellCheckClient, move empty function decls to header
* refactor: in electron::ElectronExtensionHostDelegate, move empty function decls to header
* refactor: in electron::PlatformNotificationService, move empty function decls to header
* refactor: in electron::NativeWindowViews, move empty function decls to header
* chore: move SetTouchBar() back to cc
* Revert "refactor: in auto_updater::AutoUpdater, move empty function decls to header"
This reverts commit c43d6862d32c74f63f82700a7546a732ac05ecb8.
* 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_
