Enable audio/video tag in content_shell

content/shell/shell_browser_context.cc

Index: content/shell/shell_browser_context.cc
diff --git a/content/shell/shell_browser_context.cc b/content/shell/shell_browser_context.cc
index 7cca20edfa2ad297bffa446f3ce9bd68e4753f10..deaa6e6b09bb0e5107d4b1a6c13d7a8b35854fb2 100644
--- a/content/shell/shell_browser_context.cc
+++ b/content/shell/shell_browser_context.cc
@@ -174,7 +174,7 @@ const ResourceContext& ShellBrowserContext::GetResourceContext()  {
   if (!resource_context_.get()) {
     resource_context_.reset(new ShellResourceContext(
         static_cast<ShellURLRequestContextGetter*>(GetRequestContext()),
-        GetBlobStorageContext()));
+        GetBlobStorageContext(), GetAudioManager()));
   }
   return *resource_context_.get();
 }
@@ -273,4 +273,10 @@ void ShellBrowserContext::CreateQuotaManagerAndClients() {
         special_storage_policy));
 }
 
+AudioManager* ShellBrowserContext::GetAudioManager() {
+  if (!audio_manager_.get())
+    audio_manager_ = AudioManager::Create();
+  return audio_manager_;
+}
+
 }  // namespace content