ART: Rename Handle hierarchy

Bring the names in line with normal OO principles: ConstHandle
becomes Handle, and Handle becomes MutableHandle.

Change-Id: I0f018eb7ba28bc422e3a23dd73a6cbe6fc2d2044
diff --git a/runtime/object_lock.h b/runtime/object_lock.h
index 38690bc..acddc03 100644
--- a/runtime/object_lock.h
+++ b/runtime/object_lock.h
@@ -28,7 +28,7 @@
 template <typename T>
 class ObjectLock {
  public:
-  ObjectLock(Thread* self, ConstHandle<T> object) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+  ObjectLock(Thread* self, Handle<T> object) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
   ~ObjectLock() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
@@ -40,7 +40,7 @@
 
  private:
   Thread* const self_;
-  ConstHandle<T> const obj_;
+  Handle<T> const obj_;
 
   DISALLOW_COPY_AND_ASSIGN(ObjectLock);
 };