Initialize debugger together with isolate.

third_party/WebKit/Source/platform/v8_inspector/public/V8ContextInfo.h

 // 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.
 
 #ifndef V8ContextInfo_h
 #define V8ContextInfo_h
 
 #include "platform/inspector_protocol/Collections.h"
 #include "platform/inspector_protocol/String16.h"
 
 #include <v8.h>
 
 namespace blink {
 
 class V8ContextInfo {
 public:
-    V8ContextInfo(v8::Local<v8::Context> context, bool isDefault, const String16& origin, const String16& humanReadableName, const String16& frameId)
+    V8ContextInfo(v8::Local<v8::Context> context, int contextGroupId, bool isDefault, const String16& origin, const String16& humanReadableName, const String16& frameId)
         : context(context)
+        , contextGroupId(contextGroupId)
         , isDefault(isDefault)
         , origin(origin)
         , humanReadableName(humanReadableName)
         , frameId(frameId)
     {
     }
 
     v8::Local<v8::Context> context;
+    // Each v8::Context is a part of a group. The group id is used to find appropriate
+    // V8DebuggerAgent to notify about events in the context.
+    // |contextGroupId| must be non-0.
+    int contextGroupId;
     bool isDefault;
     const String16 origin;
     const String16 humanReadableName;
     const String16 frameId;
 };
 
 using V8ContextInfoVector = protocol::Vector<V8ContextInfo>;
 
 } // namespace blink
 
 #endif // V8ContextInfo_h