Improved compile time of by adding cpp files for flag headers.

Split the mesos master, slave flags into header + source file to
improve compile time significantly. Should be no functional changes.

Review: https://reviews.apache.org/r/32558

src/Makefile.am

@@ -316,10 +316,12 @@ libmesos_no_3rdparty_la_SOURCES =					\
 	files/files.cpp							\
 	hook/manager.cpp						\
 	local/local.cpp							\
+	logging/flags.cpp						\
 	logging/logging.cpp						\
 	master/contender.cpp						\
 	master/constants.cpp						\
 	master/detector.cpp						\
+	master/flags.cpp						\
 	master/http.cpp							\
 	master/master.cpp						\
 	master/metrics.cpp						\
@@ -335,6 +337,7 @@ libmesos_no_3rdparty_la_SOURCES =					\
 	scheduler/scheduler.cpp						\
 	slave/constants.cpp						\
 	slave/gc.cpp							\
+	slave/flags.cpp							\
 	slave/http.cpp							\
 	slave/metrics.cpp						\
 	slave/monitor.cpp						\

src/logging/flags.cpp

@@ -0,0 +1,51 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "logging/flags.hpp"
+
+
+mesos::internal::logging::Flags::Flags()
+{
+  add(&Flags::quiet, "quiet", "Disable logging to stderr", false);
+
+  add(&Flags::logging_level, "logging_level",
+      "Log message at or above this level; possible values: \n"
+      "'INFO', 'WARNING', 'ERROR'; if quiet flag is used, this \n"
+      "will affect just the logs from log_dir (if specified)",
+      "INFO");
+
+  add(&Flags::log_dir, "log_dir",
+      "Directory path to put log files (no default, nothing\n"
+      "is written to disk unless specified;\n"
+      "does not affect logging to stderr).\n"
+      "NOTE: 3rd party log messages (e.g. ZooKeeper) are\n"
+      "only written to stderr!\n");
+
+  add(&Flags::logbufsecs, "logbufsecs",
+      "How many seconds to buffer log messages for", 0);
+
+  add(&Flags::initialize_driver_logging, "initialize_driver_logging",
+      "Whether to automatically initialize google logging of scheduler\n"
+      "and/or executor drivers.",
+      true);
+
+  add(&Flags::external_log_file, "external_log_file",
+      "Specified the externally managed log file. This file will be\n"
+      "exposed in the webui and HTTP api. This is useful when using\n"
+      "stderr logging as the log file is otherwise unknown to Mesos.");
+}

src/logging/flags.hpp

@@ -31,45 +31,7 @@ namespace logging {
 class Flags : public virtual flags::FlagsBase
 {
 public:
-  Flags()
-  {
-    add(&Flags::quiet,
-        "quiet",
-        "Disable logging to stderr",
-        false);
-
-    add(&Flags::logging_level,
-        "logging_level",
-        "Log message at or above this level; possible values: \n"
-        "'INFO', 'WARNING', 'ERROR'; if quiet flag is used, this \n"
-        "will affect just the logs from log_dir (if specified)",
-        "INFO");
-
-    add(&Flags::log_dir,
-        "log_dir",
-        "Directory path to put log files (no default, nothing\n"
-        "is written to disk unless specified;\n"
-        "does not affect logging to stderr).\n"
-        "NOTE: 3rd party log messages (e.g. ZooKeeper) are\n"
-        "only written to stderr!\n");
-
-    add(&Flags::logbufsecs,
-        "logbufsecs",
-        "How many seconds to buffer log messages for",
-        0);
-
-    add(&Flags::initialize_driver_logging,
-        "initialize_driver_logging",
-        "Whether to automatically initialize google logging of scheduler\n"
-        "and/or executor drivers.",
-        true);
-
-    add(&Flags::external_log_file,
-        "external_log_file",
-        "Specified the externally managed log file. This file will be\n"
-        "exposed in the webui and HTTP api. This is useful when using\n"
-        "stderr logging as the log file is otherwise unknown to Mesos.");
-  }
+  Flags();
 
   bool quiet;
   std::string logging_level;

src/master/allocator/allocator.hpp

@@ -30,6 +30,7 @@
 #include <stout/option.hpp>
 
 #include "master/flags.hpp"
+#include "messages/messages.hpp"
 
 namespace mesos {
 namespace internal {