Allows prefetch requests to live beyond the renderer by delaying

content/browser/loader/resource_dispatcher_host_impl.cc

Index: content/browser/loader/resource_dispatcher_host_impl.cc
diff --git a/content/browser/loader/resource_dispatcher_host_impl.cc b/content/browser/loader/resource_dispatcher_host_impl.cc
index 839678e30ce5cc01c6e57f60d725d6ef6e196d1b..5c8adb8ff00779097074643577020be8364fa1db 100644
--- a/content/browser/loader/resource_dispatcher_host_impl.cc
+++ b/content/browser/loader/resource_dispatcher_host_impl.cc
@@ -32,6 +32,7 @@
 #include "content/browser/fileapi/chrome_blob_storage_context.h"
 #include "content/browser/loader/async_resource_handler.h"
 #include "content/browser/loader/buffered_resource_handler.h"
+#include "content/browser/loader/detached_resource_handler.h"
 #include "content/browser/loader/cross_site_resource_handler.h"
 #include "content/browser/loader/power_save_block_resource_throttle.h"
 #include "content/browser/loader/redirect_to_file_resource_handler.h"
@@ -406,12 +407,14 @@ void ResourceDispatcherHostImpl::CancelRequestsForContext(
   for (LoaderList::iterator i = loaders_to_cancel.begin();
        i != loaders_to_cancel.end(); ++i) {
     // There is no strict requirement that this be the case, but currently
-    // downloads, streams  and transferred requests are the only requests that
-    // aren't cancelled when the associated processes go away. It may be OK for
-    // this invariant to change in the future, but if this assertion fires
-    // without the invariant changing, then it's indicative of a leak.
+    // downloads, streams, prefetches, and transferred requests are the only
+    // requests that aren't cancelled when the associated processes go away. It
+    // may be OK for this invariant to change in the future, but if this
+    // assertion fires without the invariant changing, then it's indicative of a
+    // leak.
     DCHECK((*i)->GetRequestInfo()->is_download() ||
            (*i)->GetRequestInfo()->is_stream() ||
+           DetachableType((*i)->GetRequestInfo()->GetResourceType()) ||
            (*i)->is_transferring());
   }
 #endif
@@ -694,6 +697,12 @@ void ResourceDispatcherHostImpl::DidReceiveRedirect(ResourceLoader* loader,
 
 void ResourceDispatcherHostImpl::DidReceiveResponse(ResourceLoader* loader) {
   ResourceRequestInfoImpl* info = loader->GetRequestInfo();
+
+  // Exit early in case of detachable types as they may not have a policy after
+  // the renderer is canceled.
+  if (DetachableType(info->GetResourceType()))
+    return;

[mmenke, 2013/10/11 16:39:07]

Should this only protect against messing with the offline_policy_map?  Seems
like passing in the ResourceRequestDetails may be important/relevant, though I'm
not sure what it actually does.

[jkarlin2, 2013/10/11 18:37:04]

Done.

+
   // There should be an entry in the map created when we dispatched the
   // request.
   OfflineMap::iterator policy_it(
@@ -1099,6 +1108,9 @@ void ResourceDispatcherHostImpl::BeginRequest(
   scoped_ptr<ResourceHandler> handler;
   if (sync_result) {
     handler.reset(new SyncResourceHandler(request, sync_result, this));
+  } else if (DetachableType(request_data.resource_type)) {
+    // put in detached handler
+    handler.reset(new DetachedResourceHandler(request, this));
   } else {
     handler.reset(new AsyncResourceHandler(request, this));
   }
@@ -1146,6 +1158,16 @@ void ResourceDispatcherHostImpl::BeginRequest(
   BeginRequestInternal(new_request.Pass(), handler.Pass());
 }
 
+bool ResourceDispatcherHostImpl::DetachableType(

[mmenke, 2013/10/11 16:39:07]

Suggest IsDetachableResouceType, or maybe IsResouceTypeDetachable.

[mmenke, 2013/10/11 16:39:07]

Since this is only used in this file and doesn't depend on |this|, suggest
moving it into a private namespace.

[jkarlin2, 2013/10/11 18:37:04]

Done.

[jkarlin2, 2013/10/11 18:37:04]

Done.

+    const ResourceType::Type type) const {
+  switch (type) {
+    case ResourceType::PREFETCH:
+      return true;
+    default:
+      return false;
+  }
+}
+
 void ResourceDispatcherHostImpl::OnReleaseDownloadedFile(int request_id) {
   UnregisterDownloadedTempFile(filter_->child_id(), request_id);
 }
@@ -1315,8 +1337,8 @@ void ResourceDispatcherHostImpl::ResumeDeferredNavigation(
 }
 
 // The object died, so cancel and detach all requests associated with it except
-// for downloads, which belong to the browser process even if initiated via a
-// renderer.
+// for downloads and prefetches, which belong to the browser process even if
+// initiated via a renderer.
 void ResourceDispatcherHostImpl::CancelRequestsForProcess(int child_id) {
   CancelRequestsForRoute(child_id, -1 /* cancel all */);
   registered_temp_files_.erase(child_id);
@@ -1341,12 +1363,11 @@ void ResourceDispatcherHostImpl::CancelRequestsForRoute(int child_id,
 
     GlobalRequestID id(child_id, i->first.request_id);
     DCHECK(id == i->first);
-
-    // Don't cancel navigations that are transferring to another process,
-    // since they belong to another process now.
+    // Don't cancel navigations that are expected to live beyond this process.
     if (IsTransferredNavigation(id))
       any_requests_transferring = true;
     if (!info->is_download() && !info->is_stream() &&
+        !DetachableType(info->GetResourceType()) &&
         !IsTransferredNavigation(id) &&
         (route_id == -1 || route_id == info->GetRouteID())) {
       matching_requests.push_back(id);