Backed out changeset 0aca62e914cf (bug 1376895) for asserting IsSafeToRun(), at dist\include\mozilla/SchedulerGroup.h:81 e.g. in mochitest dom/events/test/test_bug336682_1.html on Windows 10 x64. r=backout

browser/base/content/browser.js

@@ -1088,14 +1088,6 @@ function _loadURIWithFlags(browser, uri, params) {
   }
 
   let mustChangeProcess = requiredRemoteType != currentRemoteType;
-  let newFrameloader = false;
-  if (browser.getAttribute("isPreloadBrowser") == "true" && uri != "about:newtab") {
-    // Leaving about:newtab from a used to be preloaded browser should run the process
-    // selecting algorithm again.
-    mustChangeProcess = true;
-    newFrameloader = true;
-    browser.removeAttribute("isPreloadBrowser");
-  }
 
   // !requiredRemoteType means we're loading in the parent/this process.
   if (!requiredRemoteType) {
@@ -1130,8 +1122,7 @@ function _loadURIWithFlags(browser, uri, params) {
         referrer: referrer ? referrer.spec : null,
         referrerPolicy,
         remoteType: requiredRemoteType,
-        postData,
-        newFrameloader,
+        postData
       }
 
       if (params.userContextId) {
@@ -1176,11 +1167,6 @@ function LoadInOtherProcess(browser, loadOptions, historyIndex = -1) {
 // Called when a docshell has attempted to load a page in an incorrect process.
 // This function is responsible for loading the page in the correct process.
 function RedirectLoad({ target: browser, data }) {
-  if (browser.getAttribute("isPreloadBrowser") == "true") {
-    browser.removeAttribute("isPreloadBrowser");
-    data.loadOptions.newFrameloader = true;
-  }
-
   if (data.loadOptions.reloadInFreshProcess) {
     // Convert the fresh process load option into a large allocation remote type
     // to use common processing from this point.

browser/base/content/tabbrowser.xml

@@ -2119,10 +2119,6 @@
               b.setAttribute("autocompletepopup", this.getAttribute("autocompletepopup"));
             }
 
-            if (aParams.isPreloadBrowser) {
-              b.setAttribute("isPreloadBrowser", "true");
-            }
-
             if (this.hasAttribute("selectmenulist"))
               b.setAttribute("selectmenulist", this.getAttribute("selectmenulist"));
 

browser/base/content/test/urlbar/browser_urlbarKeepStateAcrossTabSwitches.js

@@ -6,7 +6,7 @@
  */
 add_task(async function() {
   let input = "i-definitely-dont-exist.example.com";
-  let tab = await BrowserTestUtils.openNewForegroundTab(gBrowser, "about:blank", false);
+  let tab = await BrowserTestUtils.openNewForegroundTab(gBrowser, "about:newtab", false);
   // NB: CPOW usage because new tab pages can be preloaded, in which case no
   // load events fire.
   await BrowserTestUtils.waitForCondition(() => !tab.linkedBrowser.contentDocument.hidden)
@@ -29,7 +29,7 @@ add_task(async function() {
 add_task(async function() {
   let input = "To be or not to be-that is the question";
   await SpecialPowers.pushPrefEnv({set: [["keyword.enabled", false]]});
-  let tab = await BrowserTestUtils.openNewForegroundTab(gBrowser, "about:blank", false);
+  let tab = await BrowserTestUtils.openNewForegroundTab(gBrowser, "about:newtab", false);
   // NB: CPOW usage because new tab pages can be preloaded, in which case no
   // load events fire.
   await BrowserTestUtils.waitForCondition(() => !tab.linkedBrowser.contentDocument.hidden)

browser/modules/E10SUtils.jsm

@@ -243,14 +243,6 @@ this.E10SUtils = {
         this.getRemoteTypeForURIObject(aURI, true, remoteType, webNav.currentURI);
     }
 
-    if (sessionHistory.count == 1 && webNav.currentURI.spec == "about:newtab") {
-      // This is possibly a preloaded browser and we're about to navigate away for
-      // the first time. On the child side there is no way to tell for sure if that
-      // is the case, so let's redirect this request to the parent to decide if a new
-      // process is needed.
-      return false;
-    }
-
     // If the URI can be loaded in the current process then continue
     return this.shouldLoadURIInThisProcess(aURI);
   },

dom/base/nsGkAtomList.h

@@ -2231,7 +2231,6 @@ GK_ATOM(DisplayPortMargins, "_displayportmargins")
 GK_ATOM(DisplayPortBase, "_displayportbase")
 GK_ATOM(AsyncScrollLayerCreationFailed, "_asyncscrolllayercreationfailed")
 GK_ATOM(forcemessagemanager, "forcemessagemanager")
-GK_ATOM(isPreloadBrowser, "isPreloadBrowser")
 
 // Names for system metrics
 GK_ATOM(color_picker_available, "color-picker-available")

dom/base/test/browser.ini

@@ -1,7 +1,6 @@
 [DEFAULT]
 support-files =
   audio.ogg
-  dummy.html
   empty.html
   file_audioLoop.html
   file_audioLoopInIframe.html
@@ -36,7 +35,6 @@ tags = mcb
 [browser_force_process_selector.js]
 skip-if = !e10s # this only makes sense with e10s-multi
 [browser_messagemanager_loadprocessscript.js]
-[browser_aboutnewtab_process_selection.js]
 [browser_messagemanager_targetframeloader.js]
 [browser_messagemanager_unload.js]
 [browser_pagehide_on_tab_close.js]

dom/base/test/browser_aboutnewtab_process_selection.js

@@ -1,76 +0,0 @@
-const TEST_URL = "http://www.example.com/browser/dom/base/test/dummy.html";
-
-var ppmm = Services.ppmm;
-
-add_task(async function(){
-  // We want to count processes in this test, so let's disable the pre-allocated process manager.
-  await SpecialPowers.pushPrefEnv({"set": [
-    ["dom.ipc.processPrelaunch.enabled", false],
-    ["dom.ipc.processCount", 10],
-    ["dom.ipc.keepProcessesAlive.web", 10],
-  ]});
-});
-
-// Ensure that the preloaded browser exists, and it's finished loading.
-async function ensurePreloaded(gBrowser) {
-  gBrowser._createPreloadBrowser();
-  // We cannot use the regular BrowserTestUtils helper for waiting here, since that
-  // would try to insert the preloaded browser, which would only break things.
-  await BrowserTestUtils.waitForCondition( () => {
-    return gBrowser._preloadedBrowser.contentDocument.readyState == "complete";
-  });
-}
-
-add_task(async function(){
-  // This test is only relevant in e10s.
-  if (!gMultiProcessBrowser)
-    return;
-
-  ppmm.releaseCachedProcesses();
-
-  // Wait for the preloaded browser to load.
-  await ensurePreloaded(gBrowser);
-
-  // Store the number of processes (note: +1 for the parent process).
-  const { childCount: originalChildCount } = ppmm;
-
-  // Use the preloaded browser and create another one.
-  BrowserOpenTab();
-  let tab1 = gBrowser.selectedTab;
-  await ensurePreloaded(gBrowser);
-
-  // Check that the process count did not change.
-  is(ppmm.childCount, originalChildCount, "Preloaded browser should not create a new content process.")
-
-  // Let's do another round.
-  BrowserOpenTab();
-  let tab2 = gBrowser.selectedTab;
-  await ensurePreloaded(gBrowser);
-
-  // Check that the process count did not change.
-  is(ppmm.childCount, originalChildCount, "Preloaded browser should (still) not create a new content process.")
-
-  // Navigate to a content page from the parent side.
-  tab2.linkedBrowser.loadURI(TEST_URL);
-  await BrowserTestUtils.browserLoaded(tab2.linkedBrowser, false, TEST_URL);
-  is(ppmm.childCount, originalChildCount + 1,
-     "Navigating away from the preloaded browser (parent side) should create a new content process.")
-
-  // Navigate to a content page from the child side.
-  await BrowserTestUtils.switchTab(gBrowser, tab1);
-  await ContentTask.spawn(tab1.linkedBrowser, null, async function() {
-    const TEST_URL = "http://www.example.com/browser/dom/base/test/dummy.html";
-    content.location.href = TEST_URL;
-  });
-  await BrowserTestUtils.browserLoaded(tab1.linkedBrowser, false, TEST_URL);
-  is(ppmm.childCount, originalChildCount + 2,
-     "Navigating away from the preloaded browser (child side) should create a new content process.")
-
-  await BrowserTestUtils.removeTab(tab1);
-  await BrowserTestUtils.removeTab(tab2);
-
-  // Since we kept alive all the processes, we can shut down the ones that do
-  // not host any tabs reliably.
-  ppmm.releaseCachedProcesses();
-  is(ppmm.childCount, originalChildCount, "We're back to the original process count.");
-});

dom/base/test/dummy.html

@@ -1,9 +0,0 @@
-<html>
-<head>
-<title>Dummy test page</title>
-<meta http-equiv="Content-Type" content="text/html;charset=utf-8"></meta>
-</head>
-<body>
-<p>Dummy test page</p>
-</body>
-</html>

dom/ipc/ContentParent.cpp

@@ -762,11 +762,11 @@ ContentParent::MinTabSelect(const nsTArray<ContentParent*>& aContentParents,
 /*static*/ already_AddRefed<ContentParent>
 ContentParent::GetNewOrUsedBrowserProcess(const nsAString& aRemoteType,
                                           ProcessPriority aPriority,
-                                          ContentParent* aOpener,
-                                          bool aPreferUsed)
+                                          ContentParent* aOpener)
 {
   nsTArray<ContentParent*>& contentParents = GetOrCreatePool(aRemoteType);
   uint32_t maxContentParents = GetMaxProcessCount(aRemoteType);
+
   if (aRemoteType.EqualsLiteral(LARGE_ALLOCATION_REMOTE_TYPE)) {
     // We never want to re-use Large-Allocation processes.
     if (contentParents.Length() >= maxContentParents) {
@@ -775,18 +775,11 @@ ContentParent::GetNewOrUsedBrowserProcess(const nsAString& aRemoteType,
                                         aOpener);
     }
   } else {
-    uint32_t numberOfParents = contentParents.Length();
-    nsTArray<nsIContentProcessInfo*> infos(numberOfParents);
+    nsTArray<nsIContentProcessInfo*> infos(contentParents.Length());
     for (auto* cp : contentParents) {
       infos.AppendElement(cp->mScriptableHelper);
     }
 
-    if (aPreferUsed && numberOfParents) {
-      // For the preloaded browser we don't want to create a new process but reuse an
-      // existing one.
-      maxContentParents = numberOfParents;
-    }
-
     nsCOMPtr<nsIContentProcessProvider> cpp =
       do_GetService("@mozilla.org/ipc/processselector;1");
     nsIContentProcessInfo* openerInfo = aOpener ? aOpener->mScriptableHelper.get() : nullptr;
@@ -1138,13 +1131,6 @@ ContentParent::CreateBrowser(const TabContext& aContext,
     remoteType.AssignLiteral(DEFAULT_REMOTE_TYPE);
   }
 
-  bool isPreloadBrowser = false;
-  nsAutoString isPreloadBrowserStr;
-  if (aFrameElement->GetAttr(kNameSpaceID_None, nsGkAtoms::isPreloadBrowser,
-                             isPreloadBrowserStr)) {
-    isPreloadBrowser = isPreloadBrowserStr.EqualsLiteral("true");
-  }
-
   RefPtr<nsIContentParent> constructorSender;
   if (isInContentProcess) {
     MOZ_ASSERT(aContext.IsMozBrowserElement() || aContext.IsJSPlugin());
@@ -1160,8 +1146,7 @@ ContentParent::CreateBrowser(const TabContext& aContext,
                                       initialPriority);
       } else {
         constructorSender =
-          GetNewOrUsedBrowserProcess(remoteType, initialPriority,
-                                     nullptr, isPreloadBrowser);
+          GetNewOrUsedBrowserProcess(remoteType, initialPriority, nullptr);
       }
       if (!constructorSender) {
         return nullptr;

dom/ipc/ContentParent.h

@@ -170,8 +170,7 @@ public:
   GetNewOrUsedBrowserProcess(const nsAString& aRemoteType = NS_LITERAL_STRING(NO_REMOTE_TYPE),
                              hal::ProcessPriority aPriority =
                              hal::ProcessPriority::PROCESS_PRIORITY_FOREGROUND,
-                             ContentParent* aOpener = nullptr,
-                             bool aPreferUsed = false);
+                             ContentParent* aOpener = nullptr);
 
   /**
    * Get or create a content process for a JS plugin. aPluginID is the id of the JS plugin

dom/security/test/mixedcontentblocker/file_frameNavigation_blankTarget.html

@@ -15,15 +15,17 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=841850
   var blankTarget = document.getElementById("blankTarget");
   blankTarget.click();
 
+  var os = SpecialPowers.Cc["@mozilla.org/observer-service;1"].
+     getService(SpecialPowers.Components.interfaces.nsIObserverService);
   var observer = {
     observe: function(subject, topic, data) {
       if(topic == "content-document-global-created" && data =="http://example.com") {
          parent.parent.postMessage({"test": "blankTarget", "msg": "opened an http link with target=_blank from a secure page"}, "http://mochi.test:8888");
-         SpecialPowers.removeAsyncObserver(observer, "content-document-global-created");
+         os.removeObserver(observer, "content-document-global-created");
       }
     }
   }
-  SpecialPowers.addAsyncObserver(observer, "content-document-global-created");
+  os.addObserver(observer, "content-document-global-created");
 
 </script>
 </body>