Remove isolate argument from handle allocation: Part I

runtime/vm/debugger.h

Index: runtime/vm/debugger.h
diff --git a/runtime/vm/debugger.h b/runtime/vm/debugger.h
index 7c4cb8a3436a79452b680be789b8741a9e4eb923..a9d054728110c47e3f7a406daa872eb2cffb42bd 100644
--- a/runtime/vm/debugger.h
+++ b/runtime/vm/debugger.h
@@ -626,7 +626,7 @@ class Debugger {
                                            const Code& code,
                                            const Array& deopt_frame,
                                            intptr_t deopt_frame_offset);
-  static RawArray* DeoptimizeToArray(Isolate* isolate,
+  static RawArray* DeoptimizeToArray(Thread* thread,
                                      StackFrame* frame,
                                      const Code& code);
   static DebuggerStackTrace* CollectStackTrace();
@@ -650,6 +650,8 @@ class Debugger {
 
   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_;