Safely cancel prerenders on threads other than the UI thread

content/browser/renderer_host/resource_dispatcher_host.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // See http://dev.chromium.org/developers/design-documents/multi-process-resource-loading
 
 #include "content/browser/renderer_host/resource_dispatcher_host.h"
 
 #include <set>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "base/shared_memory.h"
 #include "base/stl_util-inl.h"
 #include "base/time.h"
 #include "chrome/browser/download/download_file_manager.h"
 #include "chrome/browser/download/download_manager.h"
 #include "chrome/browser/download/download_request_limiter.h"
 #include "chrome/browser/download/download_util.h"
 #include "chrome/browser/download/save_file_manager.h"
 #include "chrome/browser/external_protocol_handler.h"
 #include "chrome/browser/net/url_request_tracking.h"
 #include "chrome/browser/prerender/prerender_manager.h"
+#include "chrome/browser/prerender/prerender_tracker.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/renderer_host/download_resource_handler.h"
 #include "chrome/browser/renderer_host/safe_browsing_resource_handler.h"
 #include "chrome/browser/renderer_host/save_file_resource_handler.h"
 #include "chrome/browser/safe_browsing/safe_browsing_service.h"
 #include "chrome/browser/ssl/ssl_client_auth_handler.h"
 #include "chrome/browser/ssl/ssl_manager.h"
 #include "chrome/browser/ui/login/login_prompt.h"
 #include "chrome/common/chrome_switches.h"
 #include "content/browser/appcache/chrome_appcache_service.h"
@@ skipping 386 matching lines @@
         ResolveBlobReferencesInUploadData(request_data.upload_data.get());
   }
 
   if (is_shutdown_ ||
       !ShouldServiceRequest(process_type, child_id, request_data)) {
     AbortRequestBeforeItStarts(filter_, sync_result, route_id, request_id);
     return;
   }
 
   const GURL referrer = MaybeStripReferrer(request_data.referrer);
-  const bool is_prerendering = IsPrerenderingChildRoutePair(child_id, route_id);
+  const bool is_prerendering =
+      prerender::PrerenderTracker::GetInstance()->IsPrerenderingOnIOThread(
+          child_id, route_id);
 
   // Handle a PREFETCH resource type. If prefetch is disabled, squelch the
   // request. If prerendering is enabled, trigger a prerender for the URL
   // and abort the request, to prevent double-gets. Otherwise, do a normal
   // prefetch.
   if (request_data.resource_type == ResourceType::PREFETCH) {
     // All PREFETCH requests should be GETs, but be defensive about it.
     if (request_data.method != "GET") {
       AbortRequestBeforeItStarts(filter_, sync_result, route_id, request_id);
       return;
@@ skipping 14 matching lines @@
                               is_prerendering));
       AbortRequestBeforeItStarts(filter_, sync_result, route_id, request_id);
       return;
     }
     // Otherwise, treat like a normal request, and fall-through.
   }
 
   // Abort any prerenders that spawn requests that use invalid HTTP methods.
   if (is_prerendering &&
       !prerender::PrerenderManager::IsValidHttpMethod(request_data.method)) {
-    BrowserThread::PostTask(
-        BrowserThread::UI, FROM_HERE,
-        NewRunnableFunction(
-            prerender::DestroyPreloadForRenderView,
-            resource_context.prerender_manager(),
-            child_id,
-            route_id,
-            prerender::FINAL_STATUS_INVALID_HTTP_METHOD));
-    AbortRequestBeforeItStarts(filter_, sync_result, route_id, request_id);
-    return;
+    if (prerender::PrerenderTracker::GetInstance()->TryCancelOnIOThread(
+            child_id, route_id, prerender::FINAL_STATUS_INVALID_HTTP_METHOD)) {
+      AbortRequestBeforeItStarts(filter_, sync_result, route_id, request_id);
+      return;
+    }
   }
 
   // Construct the event handler.
   scoped_refptr<ResourceHandler> handler;
   if (sync_result) {
     handler = new SyncResourceHandler(
         filter_, request_data.url, sync_result, this);
   } else {
     handler = new AsyncResourceHandler(
         filter_, route_id, request_data.url, resource_context.host_zoom_map(),
@@ skipping 1539 matching lines @@
     case ResourceType::PREFETCH:
       return net::IDLE;
 
     default:
       // When new resource types are added, their priority must be considered.
       NOTREACHED();
       return net::LOW;
   }
 }
 
-void ResourceDispatcherHost::AddPrerenderChildRoutePair(int child_id,
-                                                        int route_id) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-  DCHECK(!IsPrerenderingChildRoutePair(child_id, route_id));
-  prerender_child_route_pairs_.insert(std::make_pair(child_id, route_id));
-}
-
-void ResourceDispatcherHost::RemovePrerenderChildRoutePair(int child_id,
-                                                           int route_id) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-  DCHECK(IsPrerenderingChildRoutePair(child_id, route_id));
-  prerender_child_route_pairs_.erase(std::make_pair(child_id, route_id));
-}
-
-bool ResourceDispatcherHost::IsPrerenderingChildRoutePair(int child_id,
-                                                          int route_id) const {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-  std::pair<int, int> c_r_pair = std::make_pair(child_id, route_id);
-  return (prerender_child_route_pairs_.find(c_r_pair) !=
-            prerender_child_route_pairs_.end());
-}
-
 
 // static
 bool ResourceDispatcherHost::is_prefetch_enabled() {
   return is_prefetch_enabled_;
 }
 
 // static
 void ResourceDispatcherHost::set_is_prefetch_enabled(bool value) {
   is_prefetch_enabled_ = value;
 }
 
 // static
 bool ResourceDispatcherHost::is_prefetch_enabled_ = false;