PlzNavigate: AppCache support.

content/browser/appcache/appcache_backend_impl.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.
 
 #include "content/browser/appcache/appcache_backend_impl.h"
 
 #include "base/memory/ptr_util.h"
 #include "content/browser/appcache/appcache.h"
 #include "content/browser/appcache/appcache_group.h"
 #include "content/browser/appcache/appcache_service_impl.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/common/browser_side_navigation_policy.h"
 
 namespace content {
 
 AppCacheBackendImpl::AppCacheBackendImpl()
     : service_(NULL),
       frontend_(NULL),
       process_id_(0) {
 }
 
 AppCacheBackendImpl::~AppCacheBackendImpl() {
   hosts_.clear();
   if (service_)
     service_->UnregisterBackend(this);
 }
 
 void AppCacheBackendImpl::Initialize(AppCacheServiceImpl* service,
                                      AppCacheFrontend* frontend,
                                      int process_id) {
   DCHECK(!service_ && !frontend_ && frontend && service);
   service_ = service;
   frontend_ = frontend;
   process_id_ = process_id;
   service_->RegisterBackend(this);
 }
 
 bool AppCacheBackendImpl::RegisterHost(int id) {
-  if (GetHost(id))
+  AppCacheHost* host = GetHost(id);
+
+  if (host) {
+    // PlzNavigate. The is precreated which means we want to avoid registering
+    // it again.
+    if (IsBrowserSideNavigationEnabled()) {
+      auto found = pending_hosts_.find(id);
+      DCHECK(found != pending_hosts_.end());

[michaeln, 2016/12/05 21:52:54]

Since this |id| is given to us by a potentially compromised renderer, if its not
found in pending_host_, it might be better to return false, which indicates a
badipc and will cause the renderer to be killed.
(this comment might not apply depending... see the other comment)

[ananta, 2016/12/06 01:24:38]

The pending hosts are no longer needed with your suggestion about the service
worker pattern.

+      pending_hosts_.erase(found);
+      // Switch the frontend proxy so that the host can make IPC calls from
+      // here on.
+      host->set_frontend(frontend_);
+      return true;
+    }
     return false;
+  }
 
   hosts_[id] = base::MakeUnique<AppCacheHost>(id, frontend_, service_);
   return true;
 }
 
 bool AppCacheBackendImpl::UnregisterHost(int id) {
   return hosts_.erase(id) > 0;
 }
 
 bool AppCacheBackendImpl::SetSpawningHostId(
@@ skipping 110 matching lines @@
   auto found = hosts_.find(new_host_id);
   if (found == hosts_.end()) {
     NOTREACHED();
     return;
   }
 
   host->CompleteTransfer(new_host_id, frontend_);
   found->second = std::move(host);
 }
 
+void AppCacheBackendImpl::RegisterPrecreatedHost(
+    std::unique_ptr<AppCacheHost> host) {
+  DCHECK(IsBrowserSideNavigationEnabled());
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+
+  DCHECK(host.get());
+  // Mark the host as pending so we can avoid registering it again in the
+  // RegisterHost() call.
+  DCHECK(pending_hosts_.find(host->host_id()) == pending_hosts_.end());
+  pending_hosts_.insert(host->host_id());
+
+  DCHECK(hosts_.find(host->host_id()) == hosts_.end());
+  hosts_[host->host_id()] = std::move(host);
+}
+
 }  // namespace content