--- a/content/media/webaudio/MediaStreamAudioSourceNode.cpp
+++ b/content/media/webaudio/MediaStreamAudioSourceNode.cpp
@@ -68,22 +68,25 @@ MediaStreamAudioSourceNode::~MediaStream
  * another change request to the MediaStreamGraph thread that allows the content
  * under the new principal to flow.  This might be unnecessary if the principal
  * change is changing to be the document principal.
  */
 void
 MediaStreamAudioSourceNode::PrincipalChanged(DOMMediaStream* ms)
 {
   bool subsumes = false;
-  nsIDocument* doc = Context()->GetParentObject()->GetExtantDoc();
-  if (doc) {
-    nsIPrincipal* docPrincipal = doc->NodePrincipal();
-    nsIPrincipal* streamPrincipal = mInputStream->GetPrincipal();
-    if (NS_FAILED(docPrincipal->Subsumes(streamPrincipal, &subsumes))) {
-      subsumes = false;
+  nsPIDOMWindow* parent = Context()->GetParentObject();
+  if (parent) {
+    nsIDocument* doc = parent->GetExtantDoc();
+    if (doc) {
+      nsIPrincipal* docPrincipal = doc->NodePrincipal();
+      nsIPrincipal* streamPrincipal = mInputStream->GetPrincipal();
+      if (NS_FAILED(docPrincipal->Subsumes(streamPrincipal, &subsumes))) {
+        subsumes = false;
+      }
     }
   }
   auto stream = static_cast<AudioNodeExternalInputStream*>(mStream.get());
   stream->SetInt32Parameter(MediaStreamAudioSourceNodeEngine::ENABLE, subsumes);
 }
 
 size_t
 MediaStreamAudioSourceNode::SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const

--- a/python/mozboot/mozboot/debian.py
+++ b/python/mozboot/mozboot/debian.py
@@ -45,9 +45,11 @@ class DebianBootstrapper(BaseBootstrappe
         self.dist_id = dist_id
 
         self.packages = self.COMMON_PACKAGES + self.DISTRO_PACKAGES
 
     def install_system_packages(self):
         self.apt_install(*self.packages)
 
     def _update_package_manager(self):
-        self.run_as_root(['apt-get', 'update'])
+        #self.run_as_root(['apt-get', 'update'])
+        print 'lala'
+

--- a/python/mozboot/mozboot/ubuntu.py
+++ b/python/mozboot/mozboot/ubuntu.py
@@ -18,17 +18,17 @@ class UbuntuBootstrapper(DebianBootstrap
         # This contains add-apt-repository.
         'software-properties-common',
     ]
 
     def upgrade_mercurial(self, current):
         # Ubuntu releases up through at least 13.04 don't ship a modern
         # Mercurial. So we hook up a PPA that provides one.
         self._add_ppa('mercurial-ppa/releases')
-        self._update_package_manager()
+        # self._update_package_manager()
         self.apt_install('mercurial')
 
     def _add_ppa(self, ppa):
         # Detect PPAs that have already been added. Sadly add-apt-repository
         # doesn't do this for us and will import keys, etc every time. This
         # incurs a user prompt and is annoying, so we try to prevent it.
         list_file = ppa.replace('/', '-')
         for source in os.listdir('/etc/apt/sources.list.d'):