[Cronet] Allow UrlRequest bypass cache

components/cronet/android/cronet_url_request_adapter.cc

 // Copyright 2014 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 "cronet_url_request_adapter.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "components/cronet/android/cronet_url_request_context_adapter.h"
@@ skipping 10 matching lines @@
 
 CronetURLRequestAdapter::CronetURLRequestAdapter(
     CronetURLRequestContextAdapter* context,
     scoped_ptr<CronetURLRequestAdapterDelegate> delegate,
     const GURL& url,
     net::RequestPriority priority)
     : context_(context),
       delegate_(delegate.Pass()),
       initial_url_(url),
       initial_priority_(priority),
-      initial_method_("GET") {
+      initial_method_("GET"),
+      bypass_cache_(false) {
 }
 
 CronetURLRequestAdapter::~CronetURLRequestAdapter() {
   DCHECK(IsOnNetworkThread());
 }
 
 void CronetURLRequestAdapter::AddRequestHeader(const std::string& name,
                                                const std::string& value) {
   DCHECK(!IsOnNetworkThread());
   initial_request_headers_.SetHeader(name, value);
 }
 
+void CronetURLRequestAdapter::BypassCache() {
+  DCHECK(!IsOnNetworkThread());
+  bypass_cache_ = true;
+}
+
 bool CronetURLRequestAdapter::PostTaskToNetworkThread(
     const tracked_objects::Location& from_here,
     const base::Closure& task) {
   DCHECK(!IsOnNetworkThread());
   return context_->GetNetworkTaskRunner()->PostTask(from_here, task);
 }
 
 bool CronetURLRequestAdapter::IsOnNetworkThread() const {
   return context_->GetNetworkTaskRunner()->BelongsToCurrentThread();
 }
 
 void CronetURLRequestAdapter::Start() {
   DCHECK(IsOnNetworkThread());
   VLOG(1) << "Starting chromium request: "
           << initial_url_.possibly_invalid_spec().c_str()
           << " priority: " << RequestPriorityToString(initial_priority_);
   url_request_ = context_->GetURLRequestContext()->CreateRequest(
       initial_url_, net::DEFAULT_PRIORITY, this, NULL);
-  url_request_->SetLoadFlags(context_->default_load_flags());
+  int load_flags = context_->default_load_flags();

[mef, 2015/01/30 16:06:08]

Would it make sense to make |load_flags_| a member variable, which is
initialized by context_->default_load_flags() in constructor?

BypassCache() would set net::LOAD_DISABLE_CACHE.

Start() would use load_flags_ instead of default_load_flags().

[xunjieli, 2015/01/30 22:39:46]

Done.

+  if (bypass_cache_)
+    load_flags |= net::LOAD_DISABLE_CACHE;
+  url_request_->SetLoadFlags(load_flags);
   url_request_->set_method(initial_method_);
   url_request_->SetExtraRequestHeaders(initial_request_headers_);
   url_request_->SetPriority(initial_priority_);
   url_request_->Start();
 }
 
 void CronetURLRequestAdapter::FollowDeferredRedirect() {
   DCHECK(IsOnNetworkThread());
 
   url_request_->FollowDeferredRedirect();
@@ skipping 76 matching lines @@
   DCHECK_EQ(request, url_request_);
   if (url_request_->status().is_success())
     return false;
   VLOG(1) << "Error " << url_request_->status().error()
           << " on chromium request: " << initial_url_.possibly_invalid_spec();
   delegate_->OnError(url_request_->status().error());
   return true;
 }
 
 }  // namespace cronet