Getting rid of Isolate::current_zone() usage. Pass thread instead of isolate where it makes sense.

runtime/vm/debugger.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_DEBUGGER_H_
 #define VM_DEBUGGER_H_
 
 #include "include/dart_tools_api.h"
 
 #include "vm/object.h"
@@ skipping 497 matching lines @@
   void SetExceptionPauseInfo(Dart_ExceptionPauseInfo pause_info);
   Dart_ExceptionPauseInfo GetExceptionPauseInfo() const;
 
   void VisitObjectPointers(ObjectPointerVisitor* visitor);
 
   // Called from Runtime when a breakpoint in Dart code is reached.
   void BreakpointCallback();
 
   // Returns true if there is at least one breakpoint set in func or code.
   // Checks for both user-defined and internal temporary breakpoints.
-  bool HasBreakpoint(const Function& func);
+  // This may be called from different threads, therefore do not use the,
+  // debugger's zone.
+  bool HasBreakpoint(const Function& func, Zone* zone);
   bool HasBreakpoint(const Code& code);
 
   // Returns true if the call at address pc is patched to point to
   // a debugger stub.
   bool HasActiveBreakpoint(uword pc);
 
   // Returns a stack trace with frames corresponding to invisible functions
   // omitted. CurrentStackTrace always returns a new trace on the current stack.
   // The trace returned by StackTrace may have been cached; it is suitable for
   // use when stepping, but otherwise may be out of sync with the current stack.
@@ skipping 114 matching lines @@
                             const Library& lib,
                             const String& prefix,
                             bool include_private_fields);
 
   // Handles any events which pause vm execution.  Breakpoints,
   // interrupts, etc.
   void Pause(DebuggerEvent* event);
 
   void HandleSteppingRequest(DebuggerStackTrace* stack_trace);
 
-  Zone* zone() const {
-    return isolate_->current_zone();
-  }
-
   Isolate* isolate_;
   Dart_Port isolate_id_;  // A unique ID for the isolate in the debugger.
   bool initialized_;
 
   // ID number generator.
   intptr_t next_id_;
 
   BreakpointLocation* latent_locations_;
   BreakpointLocation* breakpoint_locations_;
   CodeBreakpoint* code_breakpoints_;
@@ skipping 29 matching lines @@
 
   friend class Isolate;
   friend class BreakpointLocation;
   DISALLOW_COPY_AND_ASSIGN(Debugger);
 };
 
 
 }  // namespace dart
 
 #endif  // VM_DEBUGGER_H_