[DevTools] fixed console.count with empty stack

third_party/WebKit/Source/platform/v8_inspector/V8Console.cpp

 // Copyright 2016 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 "platform/v8_inspector/V8Console.h"
 
 #include "platform/v8_inspector/InjectedScript.h"
 #include "platform/v8_inspector/InspectedContext.h"
 #include "platform/v8_inspector/V8Compat.h"
 #include "platform/v8_inspector/V8ConsoleMessage.h"
@@ skipping 339 matching lines @@
 }
 
 void V8Console::countCallback(const v8::FunctionCallbackInfo<v8::Value>& info)
 {
     ConsoleHelper helper(info);
 
     String16 title = helper.firstArgToString(String16());
     String16 identifier;
     if (title.isEmpty()) {
         std::unique_ptr<V8StackTraceImpl> stackTrace = V8StackTraceImpl::capture(nullptr, 0, 1);
-        if (stackTrace)
+        if (stackTrace && !stackTrace->isEmpty())
             identifier = stackTrace->topSourceURL() + ":" + String16::fromInteger(stackTrace->topLineNumber());
     } else {
         identifier = title + "@";
     }
 
     v8::Local<v8::Map> countMap;
     if (!helper.privateMap("V8Console#countMap").ToLocal(&countMap))
         return;
     int64_t count = helper.getIntFromMap(countMap, identifier, 0) + 1;
     helper.setIntOnMap(countMap, identifier, count);
@@ skipping 450 matching lines @@
             continue;
         if (name->IsString()) {
             v8::Local<v8::Value> descriptor;
             bool success = m_global->GetOwnPropertyDescriptor(m_context, v8::Local<v8::String>::Cast(name)).ToLocal(&descriptor);
             DCHECK(success);
         }
     }
 }
 
 } // namespace v8_inspector