Add 'flog' service implementation.

mojo/services/flog/cpp/flog.h

Index: mojo/services/flog/cpp/flog.h
diff --git a/mojo/services/flog/cpp/flog.h b/mojo/services/flog/cpp/flog.h
index dfa9e3bdeca2f20a5b7f1233cc688c6b84b72661..4ab91b4e07a6a92a87480aa3c0e64f57e805dfe5 100644
--- a/mojo/services/flog/cpp/flog.h
+++ b/mojo/services/flog/cpp/flog.h
@@ -95,11 +95,11 @@ namespace flog {
 // Thread-safe logger for all channels in a given process.
 class Flog {
  public:
-  static void Initialize(ApplicationImpl* app, const std::string& label) {
+  static void Initialize(Shell* shell, const std::string& label) {
     MOJO_DCHECK(!logger_);
     FlogServicePtr flog_service;
     FlogLoggerPtr flog_logger;
-    ConnectToService(app->shell(), "mojo:flog", GetProxy(&flog_service));
+    ConnectToService(shell, "mojo:flog", GetProxy(&flog_service));
     flog_service->CreateLogger(GetProxy(&flog_logger), label);
     logger_ = flog_logger.Pass();
   }
@@ -150,6 +150,8 @@ class Flog {
     logger_->LogChannelDeletion(GetTimeTicksNow(), channel_id);
   }
 
+  // TODO(dalesat): Add method for text/file/line
+
  private:
   static std::atomic_ulong last_allocated_channel_id_;
   static FlogLoggerPtr logger_;