Move sync/notifier to components/invalidation

sync/internal_api/public/base/invalidation.h

Index: sync/internal_api/public/base/invalidation.h
diff --git a/sync/internal_api/public/base/invalidation.h b/sync/internal_api/public/base/invalidation.h
index 309eb7de0147355fb481d350119dd86b508b90fb..f16d8e1469acb81d21dc67b561a62bf6ae3819ca 100644
--- a/sync/internal_api/public/base/invalidation.h
+++ b/sync/internal_api/public/base/invalidation.h
@@ -37,6 +37,7 @@ class SYNC_EXPORT Invalidation {
 
   Invalidation(const Invalidation& other);

[maniscalco, 2014/07/16 17:44:46]

Not changing in this CL, but do we need our own copy ctor?  I looked at the
implementation and I don't see how it's different from what the compiler would
provide.  Just curious.

   ~Invalidation();
+  Invalidation& operator=(const Invalidation& other);

[maniscalco, 2014/07/16 17:44:46]

Similar to my question about the cctor, do we need to provide an assignment
operator?  Is the compiler-provided one not what we want here?

If we do need one, consider adding a comment here mentioning why and another
comment down where the class member variables are defined reminding future
maintainer that when they add data members they must update the cctor and oper=.

 
   // Compares two invalidations.  The comparison ignores ack-tracking state.
   bool Equals(const Invalidation& other) const;