Move platform abstraction to base library

src/extensions/gc-extension.cc

 // Copyright 2010 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.
 
 #include "src/extensions/gc-extension.h"
-#include "src/platform.h"
+
+#include "src/base/platform/platform.h"
 
 namespace v8 {
 namespace internal {
 
 
 v8::Handle<v8::FunctionTemplate> GCExtension::GetNativeFunctionTemplate(
     v8::Isolate* isolate,
     v8::Handle<v8::String> str) {
   return v8::FunctionTemplate::New(isolate, GCExtension::GC);
 }
 
 
 void GCExtension::GC(const v8::FunctionCallbackInfo<v8::Value>& args) {
   args.GetIsolate()->RequestGarbageCollectionForTesting(
       args[0]->BooleanValue() ? v8::Isolate::kMinorGarbageCollection
                               : v8::Isolate::kFullGarbageCollection);
 }
 
 } }  // namespace v8::internal