diff --git a/content/base/public/nsContentUtils.h b/content/base/public/nsContentUtils.h
index c24c6c06adb0..3beee8ed00e7 100644
--- a/content/base/public/nsContentUtils.h
+++ b/content/base/public/nsContentUtils.h
@@ -174,14 +174,6 @@ struct ViewportInfo
 
     // Whether or not the user can zoom in and out on the page. Default is true.
     bool allowZoom;
-
-    // This is a holdover from e10s fennec, and might be removed in the future.
-    // It's a hack to work around bugs that didn't allow zooming of documents
-    // from within the parent process. It is still used in native Fennec for XUL
-    // documents, but it should probably be removed.
-    // Currently, from, within GetViewportInfo(), This is only set to false
-    // if the document is a XUL document.
-    bool autoScale;
 };
 
 struct EventNameMapping
diff --git a/content/base/src/nsContentUtils.cpp b/content/base/src/nsContentUtils.cpp
index 28cf0595ac0e..2cfdfbc899c3 100644
--- a/content/base/src/nsContentUtils.cpp
+++ b/content/base/src/nsContentUtils.cpp
@@ -5055,7 +5055,6 @@ nsContentUtils::GetViewportInfo(nsIDocument *aDocument)
   ret.defaultZoom = 1.0;
   ret.autoSize = true;
   ret.allowZoom = true;
-  ret.autoScale = true;
 
   // If the docType specifies that we are on a site optimized for mobile,
   // then we want to return specially crafted defaults for the viewport info.
@@ -5077,11 +5076,6 @@ nsContentUtils::GetViewportInfo(nsIDocument *aDocument)
     }
   }
 
-  if (aDocument->IsXUL()) {
-    ret.autoScale = false;
-    return ret;
-  }
-
   nsAutoString handheldFriendly;
   aDocument->GetHeaderData(nsGkAtoms::handheldFriendly, handheldFriendly);
 
diff --git a/mobile/android/chrome/content/browser.js b/mobile/android/chrome/content/browser.js
index 0f2f255d7a30..e791f1355cb0 100644
--- a/mobile/android/chrome/content/browser.js
+++ b/mobile/android/chrome/content/browser.js
@@ -3079,16 +3079,16 @@ Tab.prototype = {
       aMetadata.allowZoom = true;
       aMetadata.minZoom = aMetadata.maxZoom = NaN;
     }
-    if (aMetadata && aMetadata.autoScale) {
-      let scaleRatio = aMetadata.scaleRatio = ViewportHandler.getScaleRatio();
 
-      if ("defaultZoom" in aMetadata && aMetadata.defaultZoom > 0)
-        aMetadata.defaultZoom *= scaleRatio;
-      if ("minZoom" in aMetadata && aMetadata.minZoom > 0)
-        aMetadata.minZoom *= scaleRatio;
-      if ("maxZoom" in aMetadata && aMetadata.maxZoom > 0)
-        aMetadata.maxZoom *= scaleRatio;
-    }
+    let scaleRatio = aMetadata.scaleRatio = ViewportHandler.getScaleRatio();
+
+    if ("defaultZoom" in aMetadata && aMetadata.defaultZoom > 0)
+      aMetadata.defaultZoom *= scaleRatio;
+    if ("minZoom" in aMetadata && aMetadata.minZoom > 0)
+      aMetadata.minZoom *= scaleRatio;
+    if ("maxZoom" in aMetadata && aMetadata.maxZoom > 0)
+      aMetadata.maxZoom *= scaleRatio;
+
     ViewportHandler.setMetadataForDocument(this.browser.contentDocument, aMetadata);
     this.updateViewportSize(gScreenWidth);
     this.sendViewportMetadata();
@@ -4547,12 +4547,8 @@ var ViewportHandler = {
    *   height (optional int): The CSS viewport height in px.
    *   autoSize (boolean): Resize the CSS viewport when the window resizes.
    *   allowZoom (boolean): Let the user zoom in or out.
-   *   autoScale (boolean): Adjust the viewport properties to account for display density.
    */
   getViewportMetadata: function getViewportMetadata(aWindow) {
-    if (aWindow.document instanceof XULDocument)
-      return { defaultZoom: 1, autoSize: true, allowZoom: false, autoScale: false };
-
     let windowUtils = aWindow.QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIDOMWindowUtils);
 
     // viewport details found here
@@ -4577,11 +4573,11 @@ var ViewportHandler = {
       // Only check for HandheldFriendly if we don't have a viewport meta tag
       let handheldFriendly = windowUtils.getDocumentMetadata("HandheldFriendly");
       if (handheldFriendly == "true")
-        return { defaultZoom: 1, autoSize: true, allowZoom: true, autoScale: true };
+        return { defaultZoom: 1, autoSize: true, allowZoom: true };
 
       let doctype = aWindow.document.doctype;
       if (doctype && /(WAP|WML|Mobile)/.test(doctype.publicId))
-        return { defaultZoom: 1, autoSize: true, allowZoom: true, autoScale: true };
+        return { defaultZoom: 1, autoSize: true, allowZoom: true };
     }
 
     scale = this.clamp(scale, kViewportMinScale, kViewportMaxScale);
@@ -4599,8 +4595,7 @@ var ViewportHandler = {
       width: width,
       height: height,
       autoSize: autoSize,
-      allowZoom: allowZoom,
-      autoScale: true
+      allowZoom: allowZoom
     };
   },
 
@@ -4653,7 +4648,6 @@ var ViewportHandler = {
     return {
       autoSize: false,
       allowZoom: true,
-      autoScale: true,
       scaleRatio: ViewportHandler.getScaleRatio()
     };
   }