Harden yet more runtime functions

src/debug.h

 // Copyright 2012 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.
 
 #ifndef V8_DEBUG_H_
 #define V8_DEBUG_H_
 
 #include "allocation.h"
 #include "arguments.h"
 #include "assembler.h"
@@ skipping 201 matching lines @@
 // DebugInfo.
 class Debug {
  public:
   bool Load();
   void Unload();
   bool IsLoaded() { return !debug_context_.is_null(); }
   bool InDebugger() { return thread_local_.debugger_entry_ != NULL; }
   void PreemptionWhileInDebugger();
 
   Object* Break(Arguments args);
-  void SetBreakPoint(Handle<JSFunction> function,
+  bool SetBreakPoint(Handle<JSFunction> function,
                      Handle<Object> break_point_object,
                      int* source_position);
   bool SetBreakPointForScript(Handle<Script> script,
                               Handle<Object> break_point_object,
                               int* source_position,
                               BreakPositionAlignment alignment);
   void ClearBreakPoint(Handle<Object> break_point_object);
   void ClearAllBreakPoints();
   void FloodWithOneShot(Handle<JSFunction> function);
   void FloodBoundFunctionWithOneShot(Handle<JSFunction> function);
@@ skipping 786 matching lines @@
   Mutex mutex_;
   bool already_signalled_;
 
   DISALLOW_COPY_AND_ASSIGN(MessageDispatchHelperThread);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_DEBUG_H_