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 867acdc2bf549d90d9def7f0e50d0fee67adc4a9..65ef3e6e1f513301dba6244f6502a43b64f311d9 100644
--- a/src/arm/lithium-arm.cc
+++ b/src/arm/lithium-arm.cc
@@ -1509,16 +1509,10 @@ 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));
 }