Bug 1523609 - avoid triggering nsChromeRegistryChrome::CheckForNewChrome (which does main thread I/O) during shutdown of system add-ons, r=kmag.

Differential Revision: https://phabricator.services.mozilla.com/D22380

--HG--
extra : moz-landing-system : lando

browser/extensions/formautofill/api.js

@@ -130,7 +130,11 @@ this.formautofill = class extends ExtensionAPI {
     Services.mm.loadFrameScript("chrome://formautofill/content/FormAutofillFrameScript.js", true, true);
   }
 
-  onShutdown() {
+  onShutdown(reason) {
+    if (reason == "APP_SHUTDOWN") {
+      return;
+    }
+
     resProto.setSubstitution(RESOURCE_HOST, null);
 
     this.chromeHandle.destruct();

browser/extensions/webcompat-reporter/experimentalAPIs/l10n.js

@@ -17,7 +17,7 @@ let l10nManifest;
 
 this.l10n = class extends ExtensionAPI {
   onShutdown(reason) {
-    if (l10nManifest) {
+    if (reason !== "APP_SHUTDOWN" && l10nManifest) {
       Components.manager.removeBootstrappedManifestLocation(l10nManifest);
     }
   }

chrome/nsChromeRegistryChrome.cpp

@@ -28,6 +28,7 @@
 #include "mozilla/Unused.h"
 #include "mozilla/intl/LocaleService.h"
 
+#include "nsIAppStartup.h"
 #include "nsIObserverService.h"
 #include "nsIPrefBranch.h"
 #include "nsIPrefService.h"
@@ -273,6 +274,12 @@ nsChromeRegistryChrome::Observe(nsISupports* aSubject, const char* aTopic,
 
 NS_IMETHODIMP
 nsChromeRegistryChrome::CheckForNewChrome() {
+  nsCOMPtr<nsIAppStartup> appStartup = components::AppStartup::Service();
+  if (appStartup->GetShuttingDown()) {
+    MOZ_ASSERT(false, "checking for new chrome during shutdown");
+    return NS_ERROR_UNEXPECTED;
+  }
+
   mPackagesHash.Clear();
   mOverrideTable.Clear();
 

toolkit/components/startup/public/nsIAppStartup.idl

@@ -7,8 +7,7 @@
 
 interface nsIToolkitProfile;
 
-[scriptable, uuid(6621f6d5-6c04-4a0e-9e74-447db221484e)]
-
+[scriptable, builtinclass, uuid(6621f6d5-6c04-4a0e-9e74-447db221484e)]
 interface nsIAppStartup : nsISupports
 {
     /**
@@ -142,7 +141,7 @@ interface nsIAppStartup : nsISupports
     /**
      * True if the application is in the process of shutting down.
      */
-    readonly attribute boolean shuttingDown;
+    [infallible] readonly attribute boolean shuttingDown;
 
     /**
      * True if the application is in the process of starting up.

toolkit/mozapps/extensions/AddonManagerStartup.cpp

@@ -15,6 +15,7 @@
 
 #include "mozilla/ClearOnShutdown.h"
 #include "mozilla/EndianUtils.h"
+#include "mozilla/Components.h"
 #include "mozilla/Compression.h"
 #include "mozilla/LinkedList.h"
 #include "mozilla/Preferences.h"
@@ -30,6 +31,7 @@
 #include "nsAppRunner.h"
 #include "nsContentUtils.h"
 #include "nsChromeRegistry.h"
+#include "nsIAppStartup.h"
 #include "nsIDOMWindowUtils.h"  // for nsIJSRAIIHelper
 #include "nsIFileURL.h"
 #include "nsIIOService.h"
@@ -692,6 +694,13 @@ RegistryEntries::Destruct() {
   if (isInList()) {
     remove();
 
+    // No point in doing I/O to check for new chrome during shutdown, return
+    // early in that case.
+    nsCOMPtr<nsIAppStartup> appStartup = components::AppStartup::Service();
+    if (!appStartup || appStartup->GetShuttingDown()) {
+      return NS_OK;
+    }
+
     // When we remove dynamic entries from the registry, we need to rebuild it
     // in order to ensure a consistent state. See comments in Observe().
     RefPtr<nsChromeRegistry> cr = nsChromeRegistry::GetSingleton();