[turbofan] Add support for transitioning stores to double fields.

src/transitions.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_TRANSITIONS_H_
 #define V8_TRANSITIONS_H_
 
 #include "src/checks.h"
 #include "src/elements-kind.h"
 #include "src/heap/heap.h"
@@ skipping 23 matching lines @@
 // [2 + number of transitions * kTransitionSize]: start of slack
 class TransitionArray: public FixedArray {
  public:
   // Insert a new transition into |map|'s transition array, extending it
   // as necessary.
   static void Insert(Handle<Map> map, Handle<Name> name, Handle<Map> target,
                      SimpleTransitionFlag flag);
 
   static Map* SearchTransition(Map* map, PropertyKind kind, Name* name,
                                PropertyAttributes attributes);
+  static MaybeHandle<Map> SearchTransition(Handle<Map> map, PropertyKind kind,
+                                           Handle<Name> name,
+                                           PropertyAttributes attributes) {
+    if (Map* transition = SearchTransition(*map, kind, *name, attributes)) {
+      return handle(transition);
+    }
+    return MaybeHandle<Map>();
+  }
 
   static Map* SearchSpecial(Map* map, Symbol* name);
 
   static Handle<Map> FindTransitionToField(Handle<Map> map, Handle<Name> name);
 
   static Handle<String> ExpectedTransitionKey(Handle<Map> map);
 
   static Handle<Map> ExpectedTransitionTarget(Handle<Map> map) {
     DCHECK(!ExpectedTransitionKey(map).is_null());
     return Handle<Map>(GetSimpleTransition(map->raw_transitions()));
@@ skipping 245 matching lines @@
 #endif
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(TransitionArray);
 };
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TRANSITIONS_H_