Improve Array.shift() performance for small arrays.

src/arm/code-stubs-arm.cc

Index: src/arm/code-stubs-arm.cc
diff --git a/src/arm/code-stubs-arm.cc b/src/arm/code-stubs-arm.cc
index 7b2935106ff59e2995a90737fe75adf05238bbfb..2486dd7028b748b1765ffdcc99f4ed50e6eb8d79 100644
--- a/src/arm/code-stubs-arm.cc
+++ b/src/arm/code-stubs-arm.cc
@@ -305,6 +305,16 @@ void ElementsTransitionAndStoreStub::InitializeInterfaceDescriptor(
 }
 
 
+void ArrayShiftStub::InitializeInterfaceDescriptor(
+    CodeStubInterfaceDescriptor* descriptor) {
+  static Register registers[] = { r0 };
+  descriptor->register_param_count_ = 1;
+  descriptor->register_params_ = registers;
+  descriptor->deoptimization_handler_ =
+      Builtins::c_function_address(Builtins::c_ArrayShift);
+}
+
+
 void BinaryOpICStub::InitializeInterfaceDescriptor(
     CodeStubInterfaceDescriptor* descriptor) {
   static Register registers[] = { r1, r0 };