Add a target for the proxy unittests. Write tests for the var tracker....

ppapi/proxy/plugin_var_tracker.h

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef PPAPI_PROXY_PLUGIN_VAR_TRACKER_H_
 #define PPAPI_PROXY_PLUGIN_VAR_TRACKER_H_
 
 #include <map>
 #include <string>
 
@@ skipping 65 matching lines @@
   PP_Var GetHostObject(const PP_Var& plugin_object) const;
 
   // 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& plugin_object);
   int GetTrackedWithNoReferenceCountForObject(const PP_Var& plugin_object);
 
  private:
   friend struct DefaultSingletonTraits<PluginVarTracker>;
+  friend class PluginVarTrackerTest;
 
   // Represents a var as received from the host.
   struct HostVar {
     HostVar(Sender* s, int64_t i);
 
     bool operator<(const HostVar& other) const;
 
     // The host that sent us this object. This is used so we know how to send
     // back requests on this object.
     Sender* channel;
@@ skipping 57 matching lines @@
 
   // The last plugin object ID we've handed out. This must be unique for the
   // process.
   VarID last_plugin_object_id_;
 };
 
 }  // namespace proxy
 }  // namespace pp
 
 #endif  // PPAPI_PROXY_PLUGIN_VAR_TRACKER_H_