Update keygen to use correct NSS slot on ChromeOS multiprofile.

content/public/browser/resource_context.h

Index: content/public/browser/resource_context.h
diff --git a/content/public/browser/resource_context.h b/content/public/browser/resource_context.h
index ba713f60f18879cea685d26be77885d86956f03a..086fe802bedd23f614a07f23e1e1eef82777adff 100644
--- a/content/public/browser/resource_context.h
+++ b/content/public/browser/resource_context.h
@@ -5,7 +5,10 @@
 #ifndef CONTENT_PUBLIC_BROWSER_RESOURCE_CONTEXT_H_
 #define CONTENT_PUBLIC_BROWSER_RESOURCE_CONTEXT_H_
 
+#include <string>
+
 #include "base/basictypes.h"
+#include "base/callback.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/supports_user_data.h"
 #include "build/build_config.h"
@@ -20,6 +23,7 @@ class AppCacheService;
 namespace net {
 class ClientCertStore;
 class HostResolver;
+class KeygenHandler;
 class URLRequestContext;
 }
 
@@ -46,6 +50,16 @@ class CONTENT_EXPORT ResourceContext : public base::SupportsUserData {
   // Get platform ClientCertStore. May return NULL.
   virtual scoped_ptr<net::ClientCertStore> CreateClientCertStore();
 
+  // Create a platform KeygenHandler. On synchronous completion the
+  // KeygenHandler will be returned and |callback| is not run. If asynchronous
+  // initialization is necessary, NULL is returned and the KeygenHandler is
+  // passed to |callback| when it is ready.
+  virtual scoped_ptr<net::KeygenHandler> CreateKeygenHandler(

[jam, 2013/12/12 06:42:50]

nit: we prefer one way of returning data. so if it can be async, just have a
callback and no return value. in the comment you can mention that it's safe for
the embedder to run the callback in this method

[mattm, 2013/12/12 21:49:18]

Sleevi had a concern that that style of callback which can be run synchronously
can be surprising or dangerous
(https://codereview.chromium.org/53763003/diff/840001/crypto/nss_util.h#newcod...)
Thoughts?

[jam, 2013/12/13 03:16:39]

I can understand the concern, but personally I think there are numerous ways
that someone can mess up any contract if they don't read it carefully. i.e. what
if someone returns the object and then also calls the callback? or returns NULL
and calls the callback synchronously? I also tend to really prefer one way of
doing things.

[mattm, 2013/12/14 01:58:29]

Done.

+      uint32 key_size_in_bits,
+      const std::string& challenge_string,
+      const GURL& url,
+      const base::Callback<void(scoped_ptr<net::KeygenHandler>)>& callback);
+
   // Returns true if microphone access is allowed for |origin|. Used to
   // determine what level of authorization is given to |origin| to access
   // resource metadata.