Introduce a PrototypeIterator template and use it all over the place

src/deoptimizer.cc

Index: src/deoptimizer.cc
diff --git a/src/deoptimizer.cc b/src/deoptimizer.cc
index 2b39ff6965e89a1290c03d1af0ea33c20c2c963a..66a2d2554198e7e9e7ca5b0e7aed194df1435375 100644
--- a/src/deoptimizer.cc
+++ b/src/deoptimizer.cc
@@ -12,6 +12,7 @@
 #include "src/global-handles.h"
 #include "src/macro-assembler.h"
 #include "src/prettyprinter.h"
+#include "src/prototype-iterator.h"
 
 
 namespace v8 {
@@ -459,7 +460,7 @@ void Deoptimizer::DeoptimizeGlobalObject(JSObject* object) {
         reinterpret_cast<intptr_t>(object));
   }
   if (object->IsJSGlobalProxy()) {
-    Object* proto = object->GetPrototype();
+    Object* proto = SAFE_GET_PROTOTYPE_FAST(object);
     CHECK(proto->IsJSGlobalObject());
     Context* native_context = GlobalObject::cast(proto)->native_context();
     MarkAllCodeForContext(native_context);