Bug 886627 - Fix device storage tests on Android; r=dhylands

dom/devicestorage/nsDeviceStorage.cpp

@@ -637,6 +637,7 @@ OverrideRootDir::GetSingleton()
 
   sSingleton = new OverrideRootDir();
   Preferences::AddStrongObserver(sSingleton, "device.storage.overrideRootDir");
+  Preferences::AddStrongObserver(sSingleton, "device.storage.testing");
   ClearOnShutdown(&sSingleton);
 
   return sSingleton;
@@ -645,6 +646,7 @@ OverrideRootDir::GetSingleton()
 OverrideRootDir::~OverrideRootDir()
 {
   Preferences::RemoveObserver(this, "device.storage.overrideRootDir");
+  Preferences::RemoveObserver(this, "device.storage.testing");
 }
 
 NS_IMETHODIMP

dom/devicestorage/test/mochitest.ini

@@ -1,5 +1,5 @@
 [DEFAULT]
-skip-if = toolkit == 'android' || e10s #bug 781789 & bug 782275
+skip-if = e10s # bug 781789 & bug 782275
 support-files = devicestorage_common.js
 
 [test_823965.html]