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.

[michaeln, 2014/08/15 01:39:59]

There's a problem with this right here. I think we should bust the cache for
imports too, but last_update_check has the new value when we're loading imports.

I'll add a TODO for that.

[michaeln, 2014/08/15 02:53:24]

I take that back, when the main script is found to be the same, the job stops at
hat point and no imports are loaded, the worker never starts in that case.
Removing the comment and TODO.

+    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);
   }