DevTools protocol interception, blocking & modification of requests

content/browser/frame_host/navigation_request.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 "content/browser/frame_host/navigation_request.h"
 
 #include <utility>
 
 #include "base/memory/ptr_util.h"
 #include "content/browser/appcache/appcache_navigation_handle.h"
@@ skipping 132 matching lines @@
     headers->RemoveHeader("Save-Data");
 
   if (GetContentClient()->browser()->IsDataSaverEnabled(browser_context))
     headers->SetHeaderIfMissing("Save-Data", "on");
 
   headers->SetHeaderIfMissing(net::HttpRequestHeaders::kUserAgent,
                               user_agent_override.empty()
                                   ? GetContentClient()->GetUserAgent()
                                   : user_agent_override);
 
-  // Check whether DevTools wants to override user agent for this request
-  // after setting the default user agent.
-  std::string devtools_user_agent =
-      RenderFrameDevToolsAgentHost::UserAgentOverride(frame_tree_node);
-  if (!devtools_user_agent.empty()) {
-    headers->SetHeader(net::HttpRequestHeaders::kUserAgent,
-                       devtools_user_agent);
-  }
+  // Let DevTools modify the headers (e.g. UserAgent) if required.
+  RenderFrameDevToolsAgentHost::ModifyRequestHeadersIfNeeded(frame_tree_node,
+                                                             headers);
 
   // Tack an 'Upgrade-Insecure-Requests' header to outgoing navigational
   // requests, as described in
   // https://w3c.github.io/webappsec/specs/upgrade/#feature-detect
   headers->AddHeaderFromString("Upgrade-Insecure-Requests: 1");
 
   // Next, set the HTTP Origin if needed.
   if (!NeedsHTTPOrigin(headers, method))
     return;
 
@@ skipping 652 matching lines @@
   DCHECK_EQ(request_params_.has_user_gesture, begin_params_.has_user_gesture);
 
   render_frame_host->CommitNavigation(response_.get(), std::move(body_),
                                       common_params_, request_params_,
                                       is_view_source_);
 
   frame_tree_node_->ResetNavigationRequest(true);
 }
 
 }  // namespace content