Cleanup and simplify HostConfig and JsonHostConfig.

remoting/host/in_memory_host_config.h

Index: remoting/host/in_memory_host_config.h
diff --git a/remoting/host/in_memory_host_config.h b/remoting/host/in_memory_host_config.h
index 4043e83ba5103e7ba01aa4461797b27f4ad2447c..a24b8ca8fc7e38ffe90ce4f15986842bb3e735c5 100644
--- a/remoting/host/in_memory_host_config.h
+++ b/remoting/host/in_memory_host_config.h
@@ -7,37 +7,36 @@
 
 #include <string>
 
-#include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
-#include "base/synchronization/lock.h"
+#include "base/threading/non_thread_safe.h"
 #include "remoting/host/host_config.h"
 
 namespace base {
 class DictionaryValue;
-}
+}  // namespace base
 
 namespace remoting {
 
 // In-memory host config. Used by unittests.
-class InMemoryHostConfig : public MutableHostConfig {
+class InMemoryHostConfig : public MutableHostConfig,
+                           public base::NonThreadSafe {
  public:
   InMemoryHostConfig();
   virtual ~InMemoryHostConfig();
 
   // MutableHostConfig interface.
   virtual bool GetString(const std::string& path,
-                         std::string* out_value) OVERRIDE;
-  virtual bool GetBoolean(const std::string& path, bool* out_value) OVERRIDE;
+                         std::string* out_value) const OVERRIDE;
+  virtual bool GetBoolean(const std::string& path,
+                          bool* out_value) const OVERRIDE;
 
   virtual void SetString(const std::string& path,
                          const std::string& in_value) OVERRIDE;
   virtual void SetBoolean(const std::string& path, bool in_value) OVERRIDE;
 
-  virtual void Save() OVERRIDE;
+  virtual bool Save() OVERRIDE;
 
  protected:
-  // |lock_| must be locked whenever |values_| is used.
-  base::Lock lock_;
   scoped_ptr<base::DictionaryValue> values_;
 
  private: