Bug 1138746 - Do not allow e10s windows to be opened when HWA is disabled on OS X r=mconley

browser/base/content/browser.js

@@ -7315,6 +7315,14 @@ let gRemoteTabsUI = {
       return;
     }
 
+#ifdef XP_MACOSX
+    if (Services.prefs.getBoolPref("layers.acceleration.disabled")) {
+      // On OS X, "Disable Hardware Acceleration" also disables OMTC and forces
+      // a fallback to Basic Layers. This is incompatible with e10s.
+      return;
+    }
+#endif
+
     let newRemoteWindow = document.getElementById("menu_newRemoteWindow");
     let newNonRemoteWindow = document.getElementById("menu_newNonRemoteWindow");
     let autostart = Services.appinfo.browserTabsRemoteAutostart;

browser/components/customizableui/CustomizableWidgets.jsm

@@ -1103,11 +1103,18 @@ let openRemote = !Services.appinfo.browserTabsRemoteAutostart;
 let buttonLabel = openRemote ? "New e10s Window"
                               : "New Non-e10s Window";
 
+let e10sDisabled = Services.appinfo.inSafeMode;
+#ifdef XP_MACOSX
+// On OS X, "Disable Hardware Acceleration" also disables OMTC and forces
+// a fallback to Basic Layers. This is incompatible with e10s.
+e10sDisabled |= Services.prefs.getBoolPref("layers.acceleration.disabled");
+#endif
+
 CustomizableWidgets.push({
   id: "e10s-button",
   label: buttonLabel,
   tooltiptext: buttonLabel,
-  disabled: Services.appinfo.inSafeMode,
+  disabled: e10sDisabled,
   defaultArea: CustomizableUI.AREA_PANEL,
   onCommand: getCommandFunction(openRemote),
 });