Debugger: use debug break slots instead of ICs (except for calls).

src/assembler.h

Index: src/assembler.h
diff --git a/src/assembler.h b/src/assembler.h
index 2bad1eb7492f84b6287777aa729f68439f896803..fb59ceb7bd1bd22d43d705d9cb8f6082fec4e471 100644
--- a/src/assembler.h
+++ b/src/assembler.h
@@ -1085,34 +1085,11 @@ class PositionsRecorder BASE_EMBEDDED {
   // Currently jit_handler_data_ is used to store JITHandler-specific data
   // over the lifetime of a PositionsRecorder
   void* jit_handler_data_;
-  friend class PreservePositionScope;
 
   DISALLOW_COPY_AND_ASSIGN(PositionsRecorder);
 };
 
 
-class PreservePositionScope BASE_EMBEDDED {
- public:
-  explicit PreservePositionScope(PositionsRecorder* positions_recorder)
-      : positions_recorder_(positions_recorder),
-        saved_state_(positions_recorder->state_) {
-    // Reset positions so that previous ones do not accidentally get
-    // recorded within this scope.
-    positions_recorder->state_ = PositionState();
-  }
-
-  ~PreservePositionScope() {
-    positions_recorder_->state_ = saved_state_;
-  }
-
- private:
-  PositionsRecorder* positions_recorder_;
-  const PositionState saved_state_;
-
-  DISALLOW_COPY_AND_ASSIGN(PreservePositionScope);
-};
-
-
 // -----------------------------------------------------------------------------
 // Utility functions