DevTools protocol interception, blocking & modification of requests

content/browser/devtools/render_frame_devtools_agent_host.cc

Index: content/browser/devtools/render_frame_devtools_agent_host.cc
diff --git a/content/browser/devtools/render_frame_devtools_agent_host.cc b/content/browser/devtools/render_frame_devtools_agent_host.cc
index 6ecf9819126045718902f4bdea3a8b918ece6df6..4433e25d2e57f9ed3b971e3f899c77ee2983aaf8 100644
--- a/content/browser/devtools/render_frame_devtools_agent_host.cc
+++ b/content/browser/devtools/render_frame_devtools_agent_host.cc
@@ -425,13 +425,25 @@ bool RenderFrameDevToolsAgentHost::IsNetworkHandlerEnabled(
 }
 
 // static
-std::string RenderFrameDevToolsAgentHost::UserAgentOverride(
-    FrameTreeNode* frame_tree_node) {
+void RenderFrameDevToolsAgentHost::ModifyRequestHeadersIfNeeded(
+    FrameTreeNode* frame_tree_node,
+    net::HttpRequestHeaders* headers) {
   RenderFrameDevToolsAgentHost* agent_host = GetAgentHostFor(frame_tree_node);
   if (!agent_host || !agent_host->session())
-    return std::string();
-  return protocol::NetworkHandler::FromSession(agent_host->session())
-      ->UserAgentOverride();
+    return;
+  protocol::NetworkHandler* network_handler =
+      protocol::NetworkHandler::FromSession(agent_host->session());
+  std::string user_agent_override = network_handler->UserAgentOverride();
+  if (!user_agent_override.empty()) {
+    headers->SetHeader(net::HttpRequestHeaders::kUserAgent,
+                       user_agent_override);
+  }
+  if (network_handler->interception_enabled()) {
+    // Needed by DevToolsURLRequestInterceptor and will be removed by
+    // DevToolsNetworkTransaction::Start before the request is actually sent.
+    headers->SetHeader("X-DevTools-Emulate-Network-Conditions-Client-Id",
+                       agent_host->GetId());
+  }
 }
 
 // static