Add Network.setSendRequestIdHeader and use it in headless

headless/public/util/testing/generic_url_request_mocks.cc

Index: headless/public/util/testing/generic_url_request_mocks.cc
diff --git a/headless/public/util/testing/generic_url_request_mocks.cc b/headless/public/util/testing/generic_url_request_mocks.cc
index b9f94c17a7c1f8c12cd00e07c3964d9834953fe7..54e6c67c54aab9a2d7ff7df22d91685d47e72cb7 100644
--- a/headless/public/util/testing/generic_url_request_mocks.cc
+++ b/headless/public/util/testing/generic_url_request_mocks.cc
@@ -20,6 +20,7 @@ MockGenericURLRequestJobDelegate::~MockGenericURLRequestJobDelegate() {}
 
 bool MockGenericURLRequestJobDelegate::BlockOrRewriteRequest(
     const GURL& url,
+    const std::string& devtools_id,
     const std::string& method,
     const std::string& referrer,
     GenericURLRequestJob::RewriteCallback callback) {
@@ -31,6 +32,7 @@ bool MockGenericURLRequestJobDelegate::BlockOrRewriteRequest(
 const GenericURLRequestJob::HttpResponse*
 MockGenericURLRequestJobDelegate::MaybeMatchResource(
     const GURL& url,
+    const std::string& devtools_id,
     const std::string& method,
     const net::HttpRequestHeaders& request_headers) {
   return nullptr;
@@ -38,6 +40,7 @@ MockGenericURLRequestJobDelegate::MaybeMatchResource(
 
 void MockGenericURLRequestJobDelegate::OnResourceLoadComplete(
     const GURL& final_url,
+    const std::string& devtools_id,
     const std::string& mime_type,
     int http_response_code) {}