After 24 hours, bust the browser cache when checking for ServiceWorker updates

content/browser/service_worker/service_worker_context_request_handler.cc

Index: content/browser/service_worker/service_worker_context_request_handler.cc
diff --git a/content/browser/service_worker/service_worker_context_request_handler.cc b/content/browser/service_worker/service_worker_context_request_handler.cc
index 45248930d18cd3be34713d547fdf5ce6356b4532..1da3233668c4bbc4ea9442e91779c09a3cac118c 100644
--- a/content/browser/service_worker/service_worker_context_request_handler.cc
+++ b/content/browser/service_worker/service_worker_context_request_handler.cc
@@ -10,6 +10,7 @@
 #include "content/browser/service_worker/service_worker_storage.h"
 #include "content/browser/service_worker/service_worker_version.h"
 #include "content/browser/service_worker/service_worker_write_to_cache_job.h"
+#include "net/base/load_flags.h"
 #include "net/url_request/url_request.h"
 
 namespace content {
@@ -51,14 +52,28 @@ net::URLRequestJob* ServiceWorkerContextRequestHandler::MaybeCreateJob(
   }
 
   if (ShouldAddToScriptCache(request->url())) {
+    ServiceWorkerRegistration* registration =
+        context_->GetLiveRegistration(version_->registration_id());
+    DCHECK(registration);  // We're registering or updating so must be there.
+
     int64 response_id = context_->storage()->NewResourceId();
     if (response_id == kInvalidServiceWorkerResponseId)
       return NULL;
+
+    // Bypass the browser cache for initial installs and update
+    // checks after 24 hours have passed.
+    int extra_load_flags = 0;
+    base::TimeDelta time_since_last_check =
+        base::Time::Now() - registration->last_update_check();
+    if (time_since_last_check > base::TimeDelta::FromHours(24))
+      extra_load_flags = net::LOAD_BYPASS_CACHE;
+
     return new ServiceWorkerWriteToCacheJob(request,
                                             network_delegate,
                                             resource_type_,
                                             context_,
                                             version_,
+                                            extra_load_flags,
                                             response_id);
   }