Feature: Add service worker registration method to plugin API

public/service-worker.js

@@ -1,90 +0,0 @@
-/*
- I'm here to support Google Chrome App Banner on Android
- */
-
-'use strict';
-
-// Incrementing CACHE_VERSION will kick off the install event and force previously cached
-// resources to be cached again.
-const CACHE_VERSION = 1;
-let CURRENT_CACHES = {
-  offline: 'offline-v' + CACHE_VERSION
-};
-const OFFLINE_URL = 'offline.html';
-
-function createCacheBustedRequest(url) {
-  let request = new Request(url, {cache: 'reload'});
-  // See https://fetch.spec.whatwg.org/#concept-request-mode
-  // This is not yet supported in Chrome as of M48, so we need to explicitly check to see
-  // if the cache: 'reload' option had any effect.
-  if ('cache' in request) {
-    return request;
-  }
-
-  // If {cache: 'reload'} didn't have any effect, append a cache-busting URL parameter instead.
-  let bustedUrl = new URL(url, self.location.href);
-  bustedUrl.search += (bustedUrl.search ? '&' : '') + 'cachebust=' + Date.now();
-  return new Request(bustedUrl);
-}
-
-self.addEventListener('install', event => {
-  event.waitUntil(
-    // We can't use cache.add() here, since we want OFFLINE_URL to be the cache key, but
-    // the actual URL we end up requesting might include a cache-busting parameter.
-    fetch(createCacheBustedRequest(OFFLINE_URL)).then(function(response) {
-      return caches.open(CURRENT_CACHES.offline).then(function(cache) {
-        return cache.put(OFFLINE_URL, response);
-      });
-    })
-  );
-});
-
-self.addEventListener('activate', event => {
-  // Delete all caches that aren't named in CURRENT_CACHES.
-  // While there is only one cache in this example, the same logic will handle the case where
-  // there are multiple versioned caches.
-  let expectedCacheNames = Object.keys(CURRENT_CACHES).map(function(key) {
-    return CURRENT_CACHES[key];
-  });
-
-  event.waitUntil(
-    caches.keys().then(cacheNames => {
-      return Promise.all(
-        cacheNames.map(cacheName => {
-          if (expectedCacheNames.indexOf(cacheName) === -1) {
-            // If this cache name isn't present in the array of "expected" cache names,
-            // then delete it.
-            return caches.delete(cacheName);
-          }
-        })
-      );
-    })
-  );
-});
-
-self.addEventListener('fetch', event => {
-  // We only want to call event.respondWith() if this is a navigation request
-  // for an HTML page.
-  // request.mode of 'navigate' is unfortunately not supported in Chrome
-  // versions older than 49, so we need to include a less precise fallback,
-  // which checks for a GET request with an Accept: text/html header.
-  if (event.request.mode === 'navigate' ||
-      (event.request.method === 'GET' &&
-       event.request.headers.get('accept').includes('text/html'))) {
-    event.respondWith(
-      fetch(event.request).catch(error => {
-        // The catch is only triggered if fetch() throws an exception, which will most likely
-        // happen due to the server being unreachable.
-        // If fetch() returns a valid HTTP response with an response code in the 4xx or 5xx
-        // range, the catch() will NOT be called. If you need custom handling for 4xx or 5xx
-        // errors, see https://github.com/GoogleChrome/samples/tree/gh-pages/service-worker/fallback-response
-        return caches.match(OFFLINE_URL);
-      })
-    );
-  }
-
-  // If our if() condition is false, then this fetch handler won't intercept the request.
-  // If there are any other fetch handlers registered, they will get a chance to call
-  // event.respondWith(). If no fetch handlers call event.respondWith(), the request will be
-  // handled by the browser as if there were no service worker involvement.
-});