[Interpreter] Adds support for DeleteLookupSlot to Interpreter.

src/interpreter/bytecode-generator.cc

Index: src/interpreter/bytecode-generator.cc
diff --git a/src/interpreter/bytecode-generator.cc b/src/interpreter/bytecode-generator.cc
index 692eb3570f62b69cce020986a2832e7449627b0f..e2db6818fc9b8e41785b28a9a38abda860d688a8 100644
--- a/src/interpreter/bytecode-generator.cc
+++ b/src/interpreter/bytecode-generator.cc
@@ -1781,7 +1781,7 @@ void BytecodeGenerator::VisitDelete(UnaryOperation* expr) {
         break;
       }
       case VariableLocation::LOOKUP: {
-        UNIMPLEMENTED();
+        builder()->LoadLiteral(variable->name()).DeleteLookupSlot();

[mythria, 2015/12/22 11:22:55]

I load the name to the accumulator instead of passing it to the bytecode as an
operand to be inline with other variants of Delete operation. We could pass it
as an explicit operand to reduce the size. I think it is not a frequent case, so
may not save much. We would also need an additional bytecode for the wide
variant if we pass name as an operand.

[oth, 2015/12/22 16:00:56]

Yes, this seems reasonable. We should have more data on bytecode frequencies
next quarter to guide these issues.

         break;
       }
       default: