PlzNavigate: Add first version of NavigationURLLoader.

content/public/common/resource_devtools_info.h

Index: content/public/common/resource_devtools_info.h
diff --git a/content/public/common/resource_devtools_info.h b/content/public/common/resource_devtools_info.h
index c9b9ed85a07aa3a62a4efe5b816a9a93bfafbb5c..8c1e8e3433e0310892de25e5cdf3cda806d1234c 100644
--- a/content/public/common/resource_devtools_info.h
+++ b/content/public/common/resource_devtools_info.h
@@ -15,11 +15,15 @@
 
 namespace content {
 
+// Note: when modifying this structure, also update DeepCopy in
+// resource_devtools_info.cc.
 struct ResourceDevToolsInfo : base::RefCounted<ResourceDevToolsInfo> {
   typedef base::StringPairs HeadersVector;
 
   CONTENT_EXPORT ResourceDevToolsInfo();
 
+  scoped_refptr<ResourceDevToolsInfo> DeepCopy() const;
+
   int32 http_status_code;
   std::string http_status_text;
   HeadersVector request_headers;