[DevTools] Narrow down DevToolsNetworkTransaction surface.

chrome/browser/devtools/devtools_network_transaction.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 "chrome/browser/devtools/devtools_network_transaction.h"
 
 #include "chrome/browser/devtools/devtools_network_controller.h"
 #include "chrome/browser/devtools/devtools_network_interceptor.h"
 #include "net/base/load_timing_info.h"
 #include "net/base/net_errors.h"
@@ skipping 123 matching lines @@
   callback_type_ = NONE;
   callback.Run(net::ERR_INTERNET_DISCONNECTED);
 }
 
 int DevToolsNetworkTransaction::Start(
     const net::HttpRequestInfo* request,
     const net::CompletionCallback& callback,
     const net::BoundNetLog& net_log) {
   DCHECK(request);
   request_ = request;
-  interceptor_ = controller_->GetInterceptor(this);
-  interceptor_->AddThrottable(this);
 
-  if (interceptor_->ShouldFail()) {
+  std::string client_id;
+  ProcessRequest(&client_id);
+  interceptor_ = controller_->GetInterceptor(client_id);
+  if (interceptor_)
+    interceptor_->AddThrottable(this);
+
+  if (interceptor_ && interceptor_->ShouldFail()) {
     failed_ = true;
     network_transaction_->SetBeforeNetworkStartCallback(
         BeforeNetworkStartCallback());
     return net::ERR_INTERNET_DISCONNECTED;
   }
   int rv = network_transaction_->Start(request_, proxy_callback_, net_log);
   return SetupCallback(callback, rv, START);
 }
 
-void DevToolsNetworkTransaction::ProcessRequest() {
+void DevToolsNetworkTransaction::ProcessRequest(std::string* client_id) {
   DCHECK(request_);
   bool has_devtools_client_id = request_->extra_headers.HasHeader(
       kDevToolsEmulateNetworkConditionsClientId);
   if (!has_devtools_client_id)
     return;
 
   custom_request_.reset(new net::HttpRequestInfo(*request_));
   custom_request_->extra_headers.GetHeader(
-      kDevToolsEmulateNetworkConditionsClientId, &client_id_);
+      kDevToolsEmulateNetworkConditionsClientId, client_id);
   custom_request_->extra_headers.RemoveHeader(
       kDevToolsEmulateNetworkConditionsClientId);
   request_ = custom_request_.get();
 }
 
 int DevToolsNetworkTransaction::RestartIgnoringLastError(
     const net::CompletionCallback& callback) {
   if (failed_)
     return net::ERR_INTERNET_DISCONNECTED;
   int rv = network_transaction_->RestartIgnoringLastError(proxy_callback_);
@@ skipping 114 matching lines @@
 }
 
 void DevToolsNetworkTransaction::ThrottleFinished() {
   DCHECK(!callback_.is_null());
   DCHECK(callback_type_ == READ || callback_type_ == START);
   net::CompletionCallback callback = callback_;
   callback_.Reset();
   callback_type_ = NONE;
   callback.Run(throttled_result_);
 }