Allows prefetch requests to live beyond the renderer by delaying

content/browser/loader/async_resource_handler.cc

Index: content/browser/loader/async_resource_handler.cc
diff --git a/content/browser/loader/async_resource_handler.cc b/content/browser/loader/async_resource_handler.cc
index b9729f3d9aabcd95e9c01613bd06cce41c8e72bf..2e7cca55b2e7fc7bf03089e69b1b17245dff7212 100644
--- a/content/browser/loader/async_resource_handler.cc
+++ b/content/browser/loader/async_resource_handler.cc
@@ -135,10 +135,11 @@ void AsyncResourceHandler::OnDataReceivedACK(int request_id) {
 bool AsyncResourceHandler::OnUploadProgress(int request_id,
                                             uint64 position,
                                             uint64 size) {
-  ResourceMessageFilter* filter = GetFilter();
-  if (!filter)
-    return false;
-  return filter->Send(
+  const ResourceRequestInfoImpl* info = GetRequestInfo();
+  // Cancel the request if the renderer is gone unless it's detachable.
+  if (!info->filter())
+    return info->is_detached();
+  return info->filter()->Send(
       new ResourceMsg_UploadProgress(request_id, position, size));
 }
 
@@ -147,8 +148,9 @@ bool AsyncResourceHandler::OnRequestRedirected(int request_id,
                                                ResourceResponse* response,
                                                bool* defer) {
   const ResourceRequestInfoImpl* info = GetRequestInfo();
+  // Cancel the request if the renderer is gone unless it's detached.
   if (!info->filter())
-    return false;
+    return info->is_detached();
 
   *defer = did_defer_ = true;
 
@@ -172,10 +174,11 @@ bool AsyncResourceHandler::OnResponseStarted(int request_id,
   // renderer will be able to set these precisely at the time the
   // request commits, avoiding the possibility of e.g. zooming the old content
   // or of having to layout the new content twice.
-
   const ResourceRequestInfoImpl* info = GetRequestInfo();
+
+  // Cancel the request if the renderer is gone unless it's detachable.
   if (!info->filter())
-    return false;
+    return info->is_detached();
 
   if (rdh_->delegate()) {
     rdh_->delegate()->OnResponseStarted(
@@ -248,9 +251,19 @@ bool AsyncResourceHandler::OnReadCompleted(int request_id, int bytes_read,
   if (!bytes_read)
     return true;
 
+  const ResourceRequestInfoImpl* info = GetRequestInfo();
+  // Don't send any data if the resource is detached from the renderer.
+  if (info->is_detached()) {
+    buffer_->RecycleLeastRecentlyAllocated();
+    return true;
+  }
+
   ResourceMessageFilter* filter = GetFilter();
-  if (!filter)
+  // Cancel the request if the renderer is gone.
+  if (!filter) {
+    DCHECK(!info->is_detachable());
     return false;
+  }
 
   buffer_->ShrinkLastAllocation(bytes_read);
 
@@ -309,8 +322,10 @@ bool AsyncResourceHandler::OnResponseCompleted(
     const net::URLRequestStatus& status,
     const std::string& security_info) {
   const ResourceRequestInfoImpl* info = GetRequestInfo();
+
+  // Cancel the request if the renderer is gone unless it's detachable.
   if (!info->filter())
-    return false;
+    return info->is_detachable();
 
   // If we crash here, figure out what URL the renderer was requesting.
   // http://crbug.com/107692