Issue 2939 - Change default search engine to DuckDuckGo

mobile/locales/en-US/chrome/region.properties

Index: mobile/locales/en-US/chrome/region.properties
===================================================================
--- a/mobile/locales/en-US/chrome/region.properties
+++ b/mobile/locales/en-US/chrome/region.properties
@@ -2,20 +2,26 @@
 # 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/.
 
+# In Adblock Browser, we set this to DuckDuckGo, see
+# https://issues.adblockplus.org/ticket/2939.
+
 # Default search engine
-browser.search.defaultenginename=Google
+browser.search.defaultenginename=DuckDuckGo
 
 # Search engine order (order displayed in the search bar dropdown).
-browser.search.order.1=Google
-browser.search.order.2=Yahoo
-browser.search.order.3=Bing
+browser.search.order.1=DuckDuckGo
+browser.search.order.2=Google
+browser.search.order.3=Yahoo
+
+# In Adblock Browser, we want DuckDuckGo to be the default in all countries,
+# see: https://issues.adblockplus.org/ticket/2939.
 
 # These override the equivalents above when the client detects that it is in
 # US market only.
-browser.search.defaultenginename.US=Yahoo
-browser.search.order.US.1=Yahoo
-browser.search.order.US.2=Google
-browser.search.order.US.3=Bing
+# browser.search.defaultenginename.US=Yahoo
+# browser.search.order.US.1=Yahoo
+# browser.search.order.US.2=Google
+# browser.search.order.US.3=Bing
 
 # increment this number when anything gets changed in the list below.  This will
 # cause Firefox to re-read these prefs and inject any new handlers into the