Make it possible to have 1 PpapiGlobals per thread. Update unit tests.

ppapi/shared_impl/var_tracker.h

Index: ppapi/shared_impl/var_tracker.h
diff --git a/ppapi/shared_impl/var_tracker.h b/ppapi/shared_impl/var_tracker.h
index 4dc8a2db9742c4da2dc3a0cdad1d185916087f28..6d3416521fc1afafeca2b2c95dd40e412dbbd073 100644
--- a/ppapi/shared_impl/var_tracker.h
+++ b/ppapi/shared_impl/var_tracker.h
@@ -68,6 +68,12 @@ class PPAPI_SHARED_EXPORT VarTracker {
   // and their reference counts are unaffected.
   std::vector<PP_Var> GetLiveVars();
 
+  // Retrieves the internal reference counts for testing. Returns 0 if we
+  // know about the object but the corresponding value is 0, or -1 if the
+  // given object ID isn't in our map.
+  int GetRefCountForObject(const PP_Var& object);
+  int GetTrackedWithNoReferenceCountForObject(const PP_Var& object);
+
  protected:
   struct VarInfo {
     VarInfo();