Remove PreFinalizer{Callback} type aliases from view.

Internal types, no good reason to expose these to the outside.

R=
BUG=673645

Review-Url: https://codereview.chromium.org/2573783002
Cr-Commit-Position: refs/heads/master@{#438170}

third_party/WebKit/Source/platform/heap/BlinkGC.h

@@ -23,7 +23,6 @@ using VisitorCallback = void (*)(Visitor*, void* self);
 using TraceCallback = VisitorCallback;
 using WeakCallback = VisitorCallback;
 using EphemeronCallback = VisitorCallback;
-using PreFinalizerCallback = bool (*)(void*);
 
 // Simple alias to avoid heap compaction type signatures turning into
 // a sea of generic |void*|s.

third_party/WebKit/Source/platform/heap/ThreadState.h

@@ -117,8 +117,6 @@ class PLATFORM_EXPORT ThreadState {
   WTF_MAKE_NONCOPYABLE(ThreadState);
 
  public:
-  typedef std::pair<void*, PreFinalizerCallback> PreFinalizer;
-
   // See setGCState() for possible state transitions.
   enum GCState {
     NoGCScheduled,
@@ -705,6 +703,9 @@ class PLATFORM_EXPORT ThreadState {
 
   std::unique_ptr<CallbackStack> m_threadLocalWeakCallbackStack;
 
+  using PreFinalizerCallback = bool (*)(void*);
+  using PreFinalizer = std::pair<void*, PreFinalizerCallback>;
+
   // Pre-finalizers are called in the reverse order in which they are
   // registered by the constructors (including constructors of Mixin objects)
   // for an object, by processing the m_orderedPreFinalizers back-to-front.