Refactor CallStackProfile::Params into base/ for use over IPC.

base/metrics/call_stack_profile_params.h

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef BASE_METRICS_CALL_STACK_PROFILE_PARAMS_H_
+#define BASE_METRICS_CALL_STACK_PROFILE_PARAMS_H_
+
+#include <string>

[Mike Wittman, 2015/08/31 19:35:57]

All these headers are unused, except for base/base_export.h.

[sydli, 2015/08/31 20:09:42]

Done.

+#include <vector>
+
+#include "base/base_export.h"
+#include "base/profiler/stack_sampling_profiler.h"
+#include "base/time/time.h"
+
+namespace base {
+
+// Stack profiling parameters for metrics collection.
+struct BASE_EXPORT CallStackProfileParams {
+  enum Trigger {
+    UNKNOWN,
+    PROCESS_STARTUP,
+    JANKY_TASK,
+    THREAD_HUNG,
+    TRIGGER_LAST = THREAD_HUNG
+  };
+
+  // Default constructor to satisfy IPC macros.
+  CallStackProfileParams();

[Mike Wittman, 2015/08/31 19:35:57]

Is it possible to make this private, and friend the IPC code that needs it? If
not, please add a comment saying not to use it, and move after the other
constructors.

[sydli, 2015/08/31 20:09:42]

Not sure which IPC class uses this -- I'll update the comment. Something similar
is done here:
https://code.google.com/p/chromium/codesearch#chromium/src/base/location.h&sq...

+
+  // If unspecified, sets |preserve_sample_ordering| to false.
+  explicit CallStackProfileParams(Trigger trigger);
+  CallStackProfileParams(Trigger trigger, bool preserve_sample_ordering);
+
+  // The triggering event.
+  Trigger trigger;
+
+  // True if sample ordering is important and should be preserved when the
+  // associated profiles are compressed. This should only be set to true if
+  // the intended use of the requires that the sequence of call stacks within
+  // a particular profile be preserved. The default value of false provides
+  // better compression of the encoded profile and is sufficient for the
+  // typical use case of recording profiles for stack frequency analysis in
+  // aggregate.
+  bool preserve_sample_ordering;
+};
+
+}  // namespace base
+
+#endif  // BASE_METRICS_CALL_STACK_PROFILE_PARAMS_H_