Implement in-heap backing store for typed arrays.

src/x64/lithium-x64.h

Index: src/x64/lithium-x64.h
diff --git a/src/x64/lithium-x64.h b/src/x64/lithium-x64.h
index b04d607624462152b35d861478d0b4561297015a..698d9e830628ad809039a90db17370b26b9a0279 100644
--- a/src/x64/lithium-x64.h
+++ b/src/x64/lithium-x64.h
@@ -1536,6 +1536,9 @@ 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();
+  }
   LOperand* elements() { return inputs_[0]; }
   LOperand* key() { return inputs_[1]; }
   virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
@@ -2191,6 +2194,9 @@ 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();
+  }
   LOperand* elements() { return inputs_[0]; }
   LOperand* key() { return inputs_[1]; }
   LOperand* value() { return inputs_[2]; }