Pipe the devTools FrameId from blink into the browser for headless

content/public/browser/devtools_agent_host.h

Index: content/public/browser/devtools_agent_host.h
diff --git a/content/public/browser/devtools_agent_host.h b/content/public/browser/devtools_agent_host.h
index 1deed12873c4ff7d082cfe9bd3785d1025e53420..43b7dea33ce3cea69bd3127bb5efdaa454528b0a 100644
--- a/content/public/browser/devtools_agent_host.h
+++ b/content/public/browser/devtools_agent_host.h
@@ -52,6 +52,15 @@ class CONTENT_EXPORT DevToolsAgentHost
   // Returns whether particular version of DevTools protocol is supported.
   static bool IsSupportedProtocolVersion(const std::string& version);
 
+  // Returns the DevTools FrameId for the given pair of |process_id| and
+  // |frame_tree_node_id|. This is sent by the renderer and shouldn't be fully
+  // trusted.
+  // TODO(alexclarke): Remove once there is a solution for stable frame IDs. See
+  // crbug.com/715541
+  static std::string GetUntrustedDevToolsFrameIdForFrameTreeNodeId(
+      int process_id,
+      int frame_tree_node_id);
+
   // Returns DevToolsAgentHost with a given |id| or nullptr of it doesn't exist.
   static scoped_refptr<DevToolsAgentHost> GetForId(const std::string& id);