Removed a bunch of GetExistingThreadLocal calls by threading the Isolate.

src/ic.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 292 matching lines @@
       new_state == UNINITIALIZED || new_state == PREMONOMORPHIC;
   return (was_uninitialized && !is_uninitialized) ?  1 :
          (!was_uninitialized && is_uninitialized) ? -1 : 0;
 }
 
 
 void IC::PostPatching(Address address, Code* target, Code* old_target) {
   if (FLAG_type_info_threshold == 0 && !FLAG_watch_ic_patching) {
     return;
   }
-  Code* host = target->GetHeap()->isolate()->
+  Isolate* isolate = target->GetHeap()->isolate();
+  Code* host = isolate->
       inner_pointer_to_code_cache()->GetCacheEntry(address)->code;
   if (host->kind() != Code::FUNCTION) return;
 
   if (FLAG_type_info_threshold > 0 &&
       old_target->is_inline_cache_stub() &&
       target->is_inline_cache_stub()) {
     int delta = ComputeTypeInfoCountDelta(old_target->ic_state(),
                                           target->ic_state());
     // Not all Code objects have TypeFeedbackInfo.
     if (host->type_feedback_info()->IsTypeFeedbackInfo() && delta != 0) {
       TypeFeedbackInfo* info =
           TypeFeedbackInfo::cast(host->type_feedback_info());
       info->change_ic_with_type_info_count(delta);
     }
   }
   if (host->type_feedback_info()->IsTypeFeedbackInfo()) {
     TypeFeedbackInfo* info =
         TypeFeedbackInfo::cast(host->type_feedback_info());
     info->change_own_type_change_checksum();
   }
   if (FLAG_watch_ic_patching) {
     host->set_profiler_ticks(0);
-    Isolate::Current()->runtime_profiler()->NotifyICChanged();
+    isolate->runtime_profiler()->NotifyICChanged();
   }
   // TODO(2029): When an optimized function is patched, it would
   // be nice to propagate the corresponding type information to its
   // unoptimized version for the benefit of later inlining.
 }
 
 
 void IC::Clear(Address address) {
   Code* target = GetTargetAtAddress(address);
 
@@ skipping 2421 matching lines @@
 #undef ADDR
 };
 
 
 Address IC::AddressFromUtilityId(IC::UtilityId id) {
   return IC_utilities[id];
 }
 
 
 } }  // namespace v8::internal