ExtensionsRouter is the router for /extensions endpoints.

IsJSONRequest is used to check if JSON parser should be used.

PrintExtensions is just used for troubleshooting to see what the internal list of extensions DB holds It simply prints out text for all extensions when visiting /extensions/test.

RefreshExtensionsTicker updates the list of extensions by calling the specified extensionMapUpdater function.

UpdateExtensions is the handler for updating extensions.

WebStoreUpdateExtension is the handler for updating extensions made via the GET HTTP method.

AllExtensionsMap holds a mapping of extension ID to extension object.

ExtensionUpdaterTimeout is the amount of time to wait between getting new updates from DynamoDB for the list of extensions.

PDFJSExtensionID will be used to add an exception to pass the request for PDF viewer extension install from chrome web store to the extension updater proxy.

WidivineExtensionID is used to add an exception to pass the request for widivine directly to google servers.