Move CHA state keeping from Isolate to Thread.

runtime/vm/cha.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_CHA_H_
 #define VM_CHA_H_
 
 #include "vm/allocation.h"
 #include "vm/growable_array.h"
+#include "vm/thread.h"
 
 namespace dart {
 
 class Class;
 class Function;
 template <typename T> class ZoneGrowableArray;
 class String;
 
 class CHA : public StackResource {
  public:
-  explicit CHA(Isolate* isolate)
-      : StackResource(isolate),
-        isolate_(isolate),
-        leaf_classes_(isolate, 1),
-        previous_(isolate->cha()) {
-    isolate->set_cha(this);
+  explicit CHA(Thread* thread)
+      : StackResource(thread->isolate()),
+        thread_(thread),
+        leaf_classes_(thread->zone(), 1),
+        previous_(thread->cha()) {
+    thread->set_cha(this);
   }
 
   ~CHA() {
-    ASSERT(isolate_->cha() == this);
-    isolate_->set_cha(previous_);
+    ASSERT(thread_->cha() == this);
+    thread_->set_cha(previous_);
   }
 
   // Returns true if the class has subclasses.
   // Updates set of leaf classes that we register optimized code with for lazy
   // deoptimization.
   bool HasSubclasses(const Class& cls);
   bool HasSubclasses(intptr_t cid);
 
   // Return true if the class is implemented by some other class.
   // Updates set of leaf classes that we register optimized code with for lazy
   // deoptimization.
   bool IsImplemented(const Class& cls);
 
   // Returns true if any subclass of 'cls' contains the function.
   // Updates set of leaf classes that we register optimized code with for lazy
   // deoptimization.
   bool HasOverride(const Class& cls, const String& function_name);
 
   const GrowableArray<Class*>& leaf_classes() const {
     return leaf_classes_;
   }
 
  private:
   void AddToLeafClasses(const Class& cls);
 
-  Isolate* isolate_;
+  Thread* thread_;
   GrowableArray<Class*> leaf_classes_;
   CHA* previous_;
 };
 
 }  // namespace dart
 
 #endif  // VM_CHA_H_