Merge remote branch 'cros/upstream' into tempbranch

client/tests/tracing_microbenchmark/base_tracer.py

+import os
+from autotest_lib.client.bin import utils
+
+
+class Tracer(object):
+    """
+    Common interface for tracing.
+    """
+
+    tracing_dir = None
+
+    def trace_config(self, path, value):
+        """
+        Write value to a tracing config file under self.tracing_dir.
+        """
+        path = os.path.join(self.tracing_dir, path)
+        utils.open_write_close(path, value)
+
+    def warmup(self, buffer_size_kb):
+        pass
+    def cleanup(self):
+        pass
+    def start_tracing(self):
+        pass
+    def stop_tracing(self):
+        pass
+    def gather_stats(self, results):
+        pass
+    def reset_tracing(self):
+        pass