[Isolates] Move contents of Top into Isolate....

src/debug.h

 // Copyright 2006-2008 the V8 project authors. 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
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 777 matching lines @@
       Debug::NewBreak(it_.frame()->id());
     } else {
       Debug::NewBreak(StackFrame::NO_ID);
     }
 
     // Make sure that debugger is loaded and enter the debugger context.
     load_failed_ = !Debug::Load();
     if (!load_failed_) {
       // NOTE the member variable save which saves the previous context before
       // this change.
-      Top::set_context(*Debug::debug_context());
+      Isolate::Current()->set_context(*Debug::debug_context());
     }
   }
 
   ~EnterDebugger() {
     // TODO(isolates): Check to see if this is the same isolate as in the
     //                 constructor.
     Isolate* isolate = Isolate::Current();
 
     // Restore to the previous break state.
     Debug::SetBreak(break_frame_id_, break_id_);
 
     // Check for leaving the debugger.
     if (prev_ == NULL) {
       // Clear mirror cache when leaving the debugger. Skip this if there is a
       // pending exception as clearing the mirror cache calls back into
       // JavaScript. This can happen if the v8::Debug::Call is used in which
       // case the exception should end up in the calling code.
-      if (!Top::has_pending_exception()) {
+      if (!isolate->has_pending_exception()) {
         // Try to avoid any pending debug break breaking in the clear mirror
         // cache JavaScript code.
         if (isolate->stack_guard()->IsDebugBreak()) {
           Debug::set_interrupts_pending(DEBUGBREAK);
           isolate->stack_guard()->Continue(DEBUGBREAK);
         }
         Debug::ClearMirrorCache();
       }
 
       // Request preemption and debug break when leaving the last debugger entry
@@ skipping 126 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(MessageDispatchHelperThread);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // ENABLE_DEBUGGER_SUPPORT
 
 #endif  // V8_DEBUG_H_