Implement in-heap backing store for typed arrays.

src/arm/lithium-arm.h

Index: src/arm/lithium-arm.h
diff --git a/src/arm/lithium-arm.h b/src/arm/lithium-arm.h
index 2cb4ff40e82199e4d273165b1b39c35318c29bef..ddff815c3f8aeda13c58fae7e2102d896e103be7 100644
--- a/src/arm/lithium-arm.h
+++ b/src/arm/lithium-arm.h
@@ -1595,6 +1595,12 @@ class LLoadKeyed V8_FINAL : public LTemplateInstruction<1, 2, 0> {
   bool is_external() const {
     return hydrogen()->is_external();
   }
+  bool is_fixed_typed_array() const {
+    return hydrogen()->is_fixed_typed_array();
+  }
+  bool is_typed_elements() const {
+    return is_external() || is_fixed_typed_array();
+  }
 
   DECLARE_CONCRETE_INSTRUCTION(LoadKeyed, "load-keyed")
   DECLARE_HYDROGEN_ACCESSOR(LoadKeyed)
@@ -2227,6 +2233,12 @@ class LStoreKeyed V8_FINAL : public LTemplateInstruction<0, 3, 0> {
   }
 
   bool is_external() const { return hydrogen()->is_external(); }
+  bool is_fixed_typed_array() const {
+    return hydrogen()->is_fixed_typed_array();
+  }
+  bool is_typed_elements() const {
+    return is_external() || is_fixed_typed_array();
+  }
   LOperand* elements() { return inputs_[0]; }
   LOperand* key() { return inputs_[1]; }
   LOperand* value() { return inputs_[2]; }