Teach EmbeddedWorkerInstance to create a process when it needs one.

content/public/browser/service_worker_context.h

Index: content/public/browser/service_worker_context.h
diff --git a/content/public/browser/service_worker_context.h b/content/public/browser/service_worker_context.h
index 91be6eb3972c7edba4ca85751aa0b2a2fd758452..e11ff4db1bcc46ba1b35799c996f5f46d28d0459 100644
--- a/content/public/browser/service_worker_context.h
+++ b/content/public/browser/service_worker_context.h
@@ -11,6 +11,8 @@
 
 namespace content {
 
+class BrowserContext;
+
 // Represents the per-StoragePartition ServiceWorker data.  Must be used from
 // the UI thread.
 class ServiceWorkerContext {
@@ -22,9 +24,9 @@ class ServiceWorkerContext {
   typedef base::Callback<void(bool success)> ResultCallback;
 
   // Equivalent to calling navigator.serviceWorker.register(script_url, {scope:
-  // pattern}) from a renderer in |source_process_id|, except that |pattern| is
-  // an absolute URL instead of relative to some current origin.  |callback| is
-  // passed true when the JS promise is fulfilled or false when the JS
+  // pattern}) from a renderer running in |site_instance|, except that |pattern|
+  // is an absolute URL instead of relative to some current origin.  |callback|
+  // is passed true when the JS promise is fulfilled or false when the JS
   // promise is rejected.
   //
   // The registration can fail if:
@@ -35,7 +37,7 @@ class ServiceWorkerContext {
   //  * Something unexpected goes wrong, like a renderer crash or a full disk.
   virtual void RegisterServiceWorker(const Scope& pattern,
                                      const GURL& script_url,
-                                     int source_process_id,
+                                     BrowserContext* context,

[jam, 2014/04/25 04:59:30]

this seems redundant since ServiceWorkerContext should know its own
browsercontext?

[Jeffrey Yasskin, 2014/04/26 03:52:19]

At the moment, ServiceWorkerContext doesn't know its own BrowserContext, but I
can thread that through at construction instead.

                                      const ResultCallback& callback) = 0;
 
   // Equivalent to calling navigator.serviceWorker.unregister(pattern) from a