Bug 1275039 - Block e10s from being activated for release users on Windows XP. r=jimm

There's some reorganization of the code in aboutSupport to support displaying Windows XP as a string without needing to be localized, as this will require an uplift to Aurora.

MozReview-Commit-ID: IqLjEIKq0VI

toolkit/content/aboutSupport.js

@@ -49,7 +49,7 @@ var snapshotFormatters = {
     if (data.updateChannel)
       $("updatechannel-box").textContent = data.updateChannel;
 
-    let statusStrName = ".unknown";
+    let statusText = stringBundle().GetStringFromName("multiProcessStatus.unknown");
 
     // Whitelist of known values with string descriptions:
     switch (data.autoStartStatus) {
@@ -57,15 +57,18 @@ var snapshotFormatters = {
       case 1:
       case 2:
       case 4:
-      case 5:
       case 6:
       case 7:
       case 8:
       case 9:
-        statusStrName = "." + data.autoStartStatus;
+        statusText = stringBundle().GetStringFromName("multiProcessStatus." + data.autoStartStatus);
+        break;
+
+      case 10:
+        statusText = "Windows XP";
+        break;
     }
 
-    let statusText = stringBundle().GetStringFromName("multiProcessStatus" + statusStrName);
     $("multiprocess-box").textContent = stringBundle().formatStringFromName("multiProcessWindows",
       [data.numRemoteWindows, data.numTotalWindows, statusText], 3);
 

toolkit/xre/nsAppRunner.cpp

@@ -4703,6 +4703,7 @@ enum {
   kE10sDisabledForAddons = 7,
   kE10sForceDisabled = 8,
   kE10sDisabledForXPAcceleration = 9,
+  kE10sDisabledForOperatingSystem = 10,
 };
 
 #if defined(XP_WIN) || defined(XP_MACOSX)
@@ -4775,6 +4776,22 @@ MultiprocessBlockPolicy() {
   }
 #endif // XP_WIN || XP_MACOSX
 
+  if (disabledForA11y) {
+    gMultiprocessBlockPolicy = kE10sDisabledForAccessibility;
+    return gMultiprocessBlockPolicy;
+  }
+
+  /**
+   * Avoids enabling e10s for Windows XP users on the release channel.
+   */
+#if defined(XP_WIN)
+  if (Preferences::GetDefaultCString("app.update.channel").EqualsLiteral("release") &&
+      !IsVistaOrLater()) {
+    gMultiprocessBlockPolicy = kE10sDisabledForOperatingSystem;
+    return gMultiprocessBlockPolicy;
+  }
+#endif
+
 #if defined(XP_WIN)
   /**
    * We block on Windows XP if layers acceleration is requested. This is due to
@@ -4789,11 +4806,6 @@ MultiprocessBlockPolicy() {
   }
 #endif // XP_WIN
 
-  if (disabledForA11y) {
-    gMultiprocessBlockPolicy = kE10sDisabledForAccessibility;
-    return gMultiprocessBlockPolicy;
-  }
-
   /**
    * Avoids enabling e10s for certain locales that require bidi selection,
    * which currently doesn't work well with e10s.
@@ -4811,8 +4823,6 @@ MultiprocessBlockPolicy() {
     return gMultiprocessBlockPolicy;
   }
 
-
-
   /*
    * None of the blocking policies matched, so e10s is allowed to run.
    * Cache the information and return 0, indicating success.