Debugger: preserve stepping state after evaluating breakpoint condition.

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 "src/allocation.h"
 #include "src/arguments.h"
 #include "src/assembler.h"
@@ skipping 714 matching lines @@
     // Stores the way how LiveEdit has patched the stack. It is used when
     // debugger returns control back to user script.
     LiveEdit::FrameDropMode frame_drop_mode_;
 
     // When restarter frame is on stack, stores the address
     // of the pointer to function being restarted. Otherwise (most of the time)
     // stores NULL. This pointer is used with 'step in' implementation.
     Object** restarter_frame_function_pointer_;
   };
 
+
+  class PreserveDebugState {
+   public:
+    explicit PreserveDebugState(Debug* debug) : debug_(debug) {
+      size_t size = sizeof(debug_->thread_local_);
+      storage_ = NewArray<char>(size);
+      MemCopy(storage_, &debug_->thread_local_, size);
+    }
+
+    ~PreserveDebugState() {
+      size_t size = sizeof(debug_->thread_local_);
+      MemCopy(&debug_->thread_local_, storage_, size);
+      DeleteArray(storage_);
+    }
+
+   private:
+    Debug* debug_;
+    char* storage_;
+  };
+
+
   // Storage location for registers when handling debug break calls
   ThreadLocal thread_local_;
 
   Isolate* isolate_;
 
   friend class Isolate;
   friend class DebugScope;
   friend class DisableBreak;
   friend class LiveEdit;
   friend class SuppressDebug;
@@ skipping 94 matching lines @@
   // several frames above.
   // There is no calling conventions here, because it never actually gets
   // called, it only gets returned to.
   static void GenerateFrameDropperLiveEdit(MacroAssembler* masm);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_DEBUG_H_