--- a/mobile/android/app/mobile.js
+++ b/mobile/android/app/mobile.js
@@ -25,16 +25,17 @@ pref("toolkit.browser.contentViewExpire"
 
 pref("toolkit.defaultChromeURI", "chrome://browser/content/browser.xul");
 pref("browser.chromeURL", "chrome://browser/content/");
 
 // If a tab has not been active for this long (seconds), then it may be
 // turned into a zombie tab to preemptively free up memory. -1 disables time-based
 // expiration (but low-memory conditions may still require the tab to be zombified).
 pref("browser.tabs.expireTime", 900);
+pref("browser.tabs.disableThumbnailCreation", false);
 
 // Disables zombification of background tabs under memory pressure.
 // Intended for use in testing, where we don't want the tab running the
 // test harness code to be zombified.
 pref("browser.tabs.disableBackgroundZombification", false);
 
 // Control whether tab content should try to load from disk cache when network
 // is offline.

--- a/mobile/android/base/java/org/mozilla/gecko/ThumbnailHelper.java
+++ b/mobile/android/base/java/org/mozilla/gecko/ThumbnailHelper.java
@@ -1,15 +1,16 @@
 /* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
  * This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 package org.mozilla.gecko;
 
+import org.mozilla.gecko.PrefsHelper;
 import org.mozilla.gecko.annotation.WrapForJNI;
 import org.mozilla.gecko.gfx.BitmapUtils;
 import org.mozilla.gecko.mozglue.DirectBufferAllocator;
 
 import android.content.res.Resources;
 import android.graphics.Bitmap;
 import android.util.Log;
 import android.util.TypedValue;
@@ -29,16 +30,23 @@ import java.util.concurrent.atomic.Atomi
  */
 public final class ThumbnailHelper {
     private static final String LOGTAG = "GeckoThumbnailHelper";
 
     public static final float TABS_PANEL_THUMBNAIL_ASPECT_RATIO = 0.8333333f;
     public static final float TOP_SITES_THUMBNAIL_ASPECT_RATIO = 0.571428571f;  // this is a 4:7 ratio (as per UX decision)
     public static final float THUMBNAIL_ASPECT_RATIO;
 
+    private final PrefsHelper.PrefHandler mPrefObserver;
+    // Disable thumnail creation if true.
+    // This is only used in some automation tests for layout styling or painting
+    // because thumbnail creation flushes styles or paints, as a result
+    // those tests receive unexpected restyles or paints.
+    private boolean mDisableThumbnailCreation = false;
+
     static {
       // As we only want to generate one thumbnail for each tab, we calculate the
       // largest aspect ratio required and create the thumbnail based off that.
       // Any views with a smaller aspect ratio will use a cropped version of the
       // same image.
       THUMBNAIL_ASPECT_RATIO = Math.max(TABS_PANEL_THUMBNAIL_ASPECT_RATIO, TOP_SITES_THUMBNAIL_ASPECT_RATIO);
     }
 
@@ -71,19 +79,31 @@ public final class ThumbnailHelper {
 
 
         mPendingThumbnails = new LinkedList<Tab>();
         try {
             mPendingWidth = new AtomicInteger((int) res.getDimension(R.dimen.tab_thumbnail_width));
         } catch (Resources.NotFoundException nfe) { mPendingWidth = new AtomicInteger(0); }
         mWidth = -1;
         mHeight = -1;
+
+        mPrefObserver = new PrefsHelper.PrefHandlerBase() {
+            @Override
+            public void prefValue(String pref, boolean value) {
+                mDisableThumbnailCreation = value;
+            }
+        };
+        PrefsHelper.addObserver(new String[] { "browser.tabs.disableThumbnailCreation" }, mPrefObserver);
     }
 
     public void getAndProcessThumbnailFor(Tab tab) {
+        if (mDisableThumbnailCreation) {
+            return;
+        }
+
         if (AboutPages.isAboutHome(tab.getURL()) || AboutPages.isAboutPrivateBrowsing(tab.getURL())) {
             tab.updateThumbnail(null, CachePolicy.NO_STORE);
             return;
         }
 
         synchronized (mPendingThumbnails) {
             if (mPendingThumbnails.lastIndexOf(tab) > 0) {
                 // This tab is already in the queue, so don't add it again.