x64: Implement delete property in lithium backend.

src/x64/lithium-codegen-x64.h

Index: src/x64/lithium-codegen-x64.h
diff --git a/src/x64/lithium-codegen-x64.h b/src/x64/lithium-codegen-x64.h
index c99fa293b2f16532c063772cb35d70ee8e57f7aa..52409f207ba59a2acce90f1c4aa4ca1ff303158a 100644
--- a/src/x64/lithium-codegen-x64.h
+++ b/src/x64/lithium-codegen-x64.h
@@ -117,6 +117,10 @@ class LCodeGen BASE_EMBEDDED {
   bool is_done() const { return status_ == DONE; }
   bool is_aborted() const { return status_ == ABORTED; }
 
+  int strict_mode_flag() const {
+    return info_->is_strict() ? kStrictMode : kNonStrictMode;
+  }
+
   LChunk* chunk() const { return chunk_; }
   Scope* scope() const { return scope_; }
   HGraph* graph() const { return chunk_->graph(); }
@@ -226,6 +230,9 @@ class LCodeGen BASE_EMBEDDED {
   // Caller should branch on equal condition.
   void EmitIsConstructCall(Register temp);
 
+  // Emits code for pushing a constant operand.
+  void EmitPushConstantOperand(LOperand* operand);
+
   LChunk* const chunk_;
   MacroAssembler* const masm_;
   CompilationInfo* const info_;