Implement simpleperf list subcommand.

simpleperf is used to replace linux/tools/perf. And This CL implements
the list subcommand of it.

Change-Id: I3e6fe854e19cc370070d0fd8416d0aa6fa8f8e90
diff --git a/simpleperf/main.cpp b/simpleperf/main.cpp
new file mode 100644
index 0000000..017e495
--- /dev/null
+++ b/simpleperf/main.cpp
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed 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 <string.h>
+#include <string>
+#include <vector>
+
+#include <base/logging.h>
+
+#include "command.h"
+
+int main(int argc, char** argv) {
+  InitLogging(argv, android::base::StderrLogger);
+  std::vector<std::string> args;
+
+  if (argc == 1 || (argc == 2 && strcmp(argv[1], "--help") == 0)) {
+    args.push_back("help");
+  } else {
+    for (int i = 1; i < argc; ++i) {
+      args.push_back(argv[i]);
+    }
+  }
+
+  Command* command = Command::FindCommandByName(args[0]);
+  if (command == nullptr) {
+    LOG(ERROR) << "malformed command line: unknown command " << args[0];
+    return 1;
+  }
+  args.erase(args.begin());
+  bool result = command->Run(args);
+  if (result == true) {
+    LOG(DEBUG) << "run command " << args[0] << " successfully";
+  } else {
+    LOG(DEBUG) << "run command " << args[0] << "unsuccessfully";
+  }
+  return result ? 0 : 1;
+}