Use const ref for LocalFrame::LocalFrameRoot and FrameTree::Top

third_party/WebKit/Source/core/inspector/MainThreadDebugger.cpp

 /*
  * Copyright (c) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 55 matching lines @@
 #include "core/xml/XPathResult.h"
 #include "platform/UserGestureIndicator.h"
 #include "platform/wtf/PtrUtil.h"
 #include "platform/wtf/ThreadingPrimitives.h"
 #include "platform/wtf/text/StringBuilder.h"
 
 namespace blink {
 
 namespace {
 
-int FrameId(LocalFrame* frame) {
-  ASSERT(frame);
-  return WeakIdentifierMap<LocalFrame>::Identifier(frame);
+int FrameId(LocalFrame& frame) {
+  return WeakIdentifierMap<LocalFrame>::Identifier(&frame);
 }
 
 Mutex& CreationMutex() {
   DEFINE_THREAD_SAFE_STATIC_LOCAL(Mutex, mutex, (new Mutex));
   return mutex;
 }
 
 LocalFrame* ToFrame(ExecutionContext* context) {
   if (!context)
     return nullptr;
@@ skipping 119 matching lines @@
     GetV8Inspector()->exceptionThrown(
         script_state->GetContext(), ToV8InspectorStringView(default_message),
         exception, ToV8InspectorStringView(message),
         ToV8InspectorStringView(url), location->LineNumber(),
         location->ColumnNumber(), location->TakeStackTrace(),
         location->ScriptId());
   }
 }
 
 int MainThreadDebugger::ContextGroupId(LocalFrame* frame) {
-  LocalFrame* local_frame_root = frame->LocalFrameRoot();
+  LocalFrame& local_frame_root = frame->LocalFrameRoot();
   return FrameId(local_frame_root);
 }
 
 MainThreadDebugger* MainThreadDebugger::Instance() {
   DCHECK(IsMainThread());
   ThreadDebugger* debugger =
       ThreadDebugger::From(V8PerIsolateData::MainThreadIsolate());
   DCHECK(debugger && !debugger->IsWorker());
   return static_cast<MainThreadDebugger*>(debugger);
 }
@@ skipping 236 matching lines @@
                context, nodes, index++,
                ToV8(node, info.Holder(), info.GetIsolate()))
                .FromMaybe(false))
         return;
     }
     info.GetReturnValue().Set(nodes);
   }
 }
 
 }  // namespace blink