[DevTools] Remove handlers = browser from protocol definition.

content/browser/devtools/protocol/memory_handler.cc

 // Copyright 2015 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/devtools/protocol/memory_handler.h"
 
 #include "base/memory/memory_pressure_listener.h"
 #include "base/strings/stringprintf.h"
 #include "content/browser/memory/memory_pressure_controller_impl.h"
 #include "content/public/common/content_features.h"
@@ skipping 28 matching lines @@
   } else {
     return Response::InternalError(base::StringPrintf(
         "Invalid memory pressure level '%s'", level.c_str()));
   }
 
   MemoryPressureControllerImpl::GetInstance()
       ->SimulatePressureNotificationInAllProcesses(parsed_level);
   return Response::OK();
 }
 
+MemoryHandler::Response MemoryHandler::GetDOMCounters(
+    int* documents,
+    int* nodes,
+    int* event_listeners) {
+  return Response::FallThrough();
+}
+
 }  // namespace memory
 }  // namespace devtools
 }  // namespace content