debounce tab update events

auditors @bbondy

lib/browser/api/extensions.js

@@ -14,6 +14,18 @@ var tabs = {}
 
 const TAB_ID_NONE = -1
 
+function debounce (fn, bufferInterval, ...args) {
+  let timeout
+  return (...args2) => {
+    clearTimeout(timeout)
+    let a = args || []
+    if (args2 && args2.constructor === Array) {
+      a = a.concat(args2)
+    }
+    timeout = setTimeout(fn.apply.bind(fn, this, a), bufferInterval)
+  }
+}
+
 var getResourceURL = function (extensionId, path) {
   path = String(path)
   if (!path.length || path[0] != '/')
@@ -350,45 +362,56 @@ app.on('web-contents-created', function (event, tab) {
   if (tabId === -1)
     return
 
+  const updateTabDebounce = debounce(chromeTabsUpdated, 5)
+
   tab.on('page-title-updated', function () {
-    chromeTabsUpdated(tabId)
+    updateTabDebounce(tabId)
   })
   tab.on('did-fail-load', function () {
-    chromeTabsUpdated(tabId)
+    updateTabDebounce(tabId)
   })
   tab.on('did-fail-provisional-load', function () {
-    chromeTabsUpdated(tabId)
+    updateTabDebounce(tabId)
   })
   tab.on('did-attach', function () {
     createTabValue(tab)
-    chromeTabsUpdated(tabId)
+    chromeTabsUpdated(tabId)  // immediate
+  })
+  tab.on('did-detach', () => {
+    chromeTabsUpdated(tabId)  // immediate
   })
   tab.on('did-start-loading', function () {
-    chromeTabsUpdated(tabId)
+    updateTabDebounce(tabId)
   })
   tab.on('did-stop-loading', function () {
-    chromeTabsUpdated(tabId)
+    updateTabDebounce(tabId)
   })
   tab.on('navigation-entry-commited', function (evt, url) {
     createTabValue(tab)
-    chromeTabsUpdated(tabId)
+    updateTabDebounce(tabId)
   })
   tab.on('did-navigate', function (evt, url) {
     createTabValue(tab)
-    chromeTabsUpdated(tabId)
+    chromeTabsUpdated(tabId)  // immediate
+  })
+  tab.on('did-navigate-in-page', function (evt, url, isMainFrame) {
+    updateTabDebounce(tabId)
   })
   tab.on('load-start', function (evt, url, isMainFrame, isErrorPage) {
     if (isMainFrame) {
       createTabValue(tab)
-      chromeTabsUpdated(tabId)
+      chromeTabsUpdated(tabId)  // immediate
     }
   })
   tab.on('did-finish-load', function () {
     createTabValue(tab)
-    chromeTabsUpdated(tabId)
+    updateTabDebounce(tabId)
   })
   tab.on('set-active', function (evt, active) {
-    chromeTabsUpdated(tabId)
+    chromeTabsUpdated(tabId)  // immediate
+  })
+  tab.on('set-tab-index', function (evt, index) {
+    updateTabDebounce(tabId)
   })
   tab.on('destroyed', function () {
     chromeTabsRemoved(tabId)