Introduce basic type feedback for for-in statements to avoid deopts.

src/arm/full-codegen-arm.cc

Index: src/arm/full-codegen-arm.cc
diff --git a/src/arm/full-codegen-arm.cc b/src/arm/full-codegen-arm.cc
index 418e0c5f7c9cfbcfba491a0b1021e1f95492a9dd..8639698051041118a6eb108706dde664df16ff80 100644
--- a/src/arm/full-codegen-arm.cc
+++ b/src/arm/full-codegen-arm.cc
@@ -1004,6 +1004,16 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   // We got a fixed array in register r0. Iterate through that.
   Label non_proxy;
   __ bind(&fixed_array);
+
+  Handle<JSGlobalPropertyCell> cell =
+      isolate()->factory()->NewJSGlobalPropertyCell(
+          Handle<Object>(
+              Smi::FromInt(TypeFeedbackCells::kForInFastCaseMarker)));
+  RecordTypeFeedbackCell(stmt->PrepareId(), cell);
+  __ LoadHeapObject(r1, cell);
+  __ mov(r2, Operand(Smi::FromInt(TypeFeedbackCells::kForInSlowCaseMarker)));
+  __ str(r2, FieldMemOperand(r1, JSGlobalPropertyCell::kValueOffset));
+
   __ mov(r1, Operand(Smi::FromInt(1)));  // Smi indicates slow check
   __ ldr(r2, MemOperand(sp, 0 * kPointerSize));  // Get enumerated object
   STATIC_ASSERT(FIRST_JS_PROXY_TYPE == FIRST_SPEC_OBJECT_TYPE);