[WIP] Speculatively launch Service Workers on mouse/touch events.

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 72650154c721daaa19b9511aabc62f9ff028e167..f1813d3a1d29be97337b8e469593de64167df483 100644
--- a/content/public/browser/service_worker_context.h
+++ b/content/public/browser/service_worker_context.h
@@ -12,6 +12,10 @@
 #include "content/public/browser/service_worker_usage_info.h"
 #include "url/gurl.h"
 
+namespace blink {
+enum class WebNavigationHintType;
+}
+
 namespace content {
 
 // Represents the per-StoragePartition ServiceWorker data.
@@ -105,6 +109,20 @@ class ServiceWorkerContext {
   // be called on the UI thread.
   virtual void ClearAllServiceWorkersForTest(const base::Closure& callback) = 0;
 
+  // Starts a Service Worker for |document_url| for a navigation hint in the
+  // specified render process |render_process_id|. Must be called from the IO
+  // thread. The |callback| will always be called on the IO thred.
+  // This method can fail if:
+  //  * No Service Worker was registered for |document_url|.
+  //  * The specified render process is suitable for loading |document_url|.
+  //    This check is done by RenderProcessHostImpl::IsSuitableHost().
+  //  * Something unexpected goes wrong, like a renderer crash.
+  virtual void StartServiceWorkerForNavigationHint(
+      const GURL& document_url,
+      blink::WebNavigationHintType type,
+      int render_process_id,
+      const ResultCallback& callback) = 0;
+
  protected:
   ServiceWorkerContext() {}
   virtual ~ServiceWorkerContext() {}