Revert Dart_PropagateError until I can track down the problems in

runtime/vm/debugger.h

 // Copyright (c) 2011, 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 "vm/object.h"
 
 namespace dart {
@@ skipping 114 matching lines @@
   void Shutdown();
   bool IsActive();
 
   void SetBreakpointHandler(BreakpointHandler* handler);
 
   RawFunction* ResolveFunction(const Library& library,
                                const String& class_name,
                                const String& function_name);
 
   // Set breakpoint at closest location to function entry.
-  Breakpoint* SetBreakpointAtEntry(const Function& target_function,
-                                   Error* error);
+  Breakpoint* SetBreakpointAtEntry(const Function& target_function);
   Breakpoint* SetBreakpointAtLine(const String& script_url,
-                                  intptr_t line_number,
-                                  Error* error);
+                                  intptr_t line_number);
 
   void RemoveBreakpoint(Breakpoint* bpt);
 
   void VisitObjectPointers(ObjectPointerVisitor* visitor);
 
   // Returns NULL if no breakpoint exists for the given address.
   Breakpoint* GetBreakpoint(uword breakpoint_address);
 
   // Called from Runtime when a breakpoint in Dart code is reached.
   void BreakpointCallback();
 
   RawArray* GetInstanceFields(const Instance& obj);
   RawArray* GetStaticFields(const Class& cls);
 
   // Utility functions.
   static const char* QualifiedFunctionName(const Function& func);
 
   RawObject* GetInstanceField(const Class& cls,
                               const String& field_name,
                               const Instance& object);
   RawObject* GetStaticField(const Class& cls,
                             const String& field_name);
 
  private:
   Breakpoint* SetBreakpoint(const Function& target_function,
-                            intptr_t token_index,
-                            Error* error);
+                            intptr_t token_index);
   void UnsetBreakpoint(Breakpoint* bpt);
   Breakpoint* NewBreakpoint(const Function& func, intptr_t pc_desc_index);
   void RegisterBreakpoint(Breakpoint* bpt);
   Breakpoint* GetBreakpointByFunction(const Function& func,
                                       intptr_t token_index);
 
   Isolate* isolate_;
   bool initialized_;
   BreakpointHandler* bp_handler_;
   Breakpoint* breakpoints_;
   DISALLOW_COPY_AND_ASSIGN(Debugger);
 };
 
 
 }  // namespace dart
 
 #endif  // VM_DEBUGGER_H_