Create a common subclass for arrays

src/arm/lithium-arm.cc

Index: src/arm/lithium-arm.cc
diff --git a/src/arm/lithium-arm.cc b/src/arm/lithium-arm.cc
index 1eb4aff2bc7198187e1c36230e9cf6411f0cb10d..3196d0e0e143a7a092268c9d56f9bc6d4dbc8a31 100644
--- a/src/arm/lithium-arm.cc
+++ b/src/arm/lithium-arm.cc
@@ -1515,16 +1515,10 @@ LInstruction* LChunkBuilder::DoJSArrayLength(HJSArrayLength* instr) {
 }
 
 
-LInstruction* LChunkBuilder::DoExternalArrayLength(
-    HExternalArrayLength* instr) {
+LInstruction* LChunkBuilder::DoFixedArrayBaseLength(
+    HFixedArrayBaseLength* instr) {
   LOperand* array = UseRegisterAtStart(instr->value());
-  return DefineAsRegister(new LExternalArrayLength(array));
-}
-
-
-LInstruction* LChunkBuilder::DoFixedArrayLength(HFixedArrayLength* instr) {
-  LOperand* array = UseRegisterAtStart(instr->value());
-  return DefineAsRegister(new LFixedArrayLength(array));
+  return DefineAsRegister(new LFixedArrayBaseLength(array));
 }