[inspector] fix compilation on win and linux

test/inspector/inspector-test.cc

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if !defined(_WIN32) && !defined(_WIN64)
 #include <unistd.h>  // NOLINT
 #endif               // !defined(_WIN32) && !defined(_WIN64)
 
 #include "include/libplatform/libplatform.h"
 #include "include/v8.h"
@@ skipping 109 matching lines @@
       : v8::Extension("v8_inspector/setTimeout",
                       "native function setTimeout();") {}
 
   virtual v8::Local<v8::FunctionTemplate> GetNativeFunctionTemplate(
       v8::Isolate* isolate, v8::Local<v8::String> name) {
     return v8::FunctionTemplate::New(isolate, SetTimeoutExtension::SetTimeout);
   }
 
  private:
   static void SetTimeout(const v8::FunctionCallbackInfo<v8::Value>& args) {
-    v8::Isolate* isolate = args.GetIsolate();
     if (args.Length() != 2 || !args[1]->IsNumber() ||
         (!args[0]->IsFunction() && !args[0]->IsString()) ||
         args[1].As<v8::Number>()->Value() != 0.0) {
       fprintf(stderr,
               "Internal error: only setTimeout(function, 0) is supported.");
       Exit();
     }
     v8::Local<v8::Context> context = args.GetIsolate()->GetCurrentContext();
     if (args[0]->IsFunction()) {
       TaskRunner::FromContext(context)->Append(new SetTimeoutTask(
@@ skipping 86 matching lines @@
       Exit();
     }
     v8_inspector::String16 source =
         v8_inspector::String16::fromUTF8(chars.start(), chars.length());
     frontend_runner.Append(new ExecuteStringTask(source));
   }
 
   frontend_runner.Join();
   return 0;
 }