Collect unclean shutdown debug information

components/browser_watcher/stability_report.proto

Index: components/browser_watcher/stability_report.proto
diff --git a/components/browser_watcher/stability_report.proto b/components/browser_watcher/stability_report.proto
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+// Copyright 2016 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.
+
+syntax = "proto2";
+
+option optimize_for = LITE_RUNTIME;
+
+package browser_watcher;
+
+// The state of the system on which Chrome is running (shutting down, battery
+// level, load, etc.).
+message SystemState {}
+
+message CodeModule {
+  // The base address of this code module as it was loaded by the process.
+  optional int64 base_address = 1;
+
+  // The size of the code module.
+  optional int64 size = 2;
+
+  // The path or file name that the code module was loaded from.
+  optional string code_file = 3;
+
+  // An identifying string used to discriminate between multiple versions and
+  // builds of the same code module.  This may contain a uuid, timestamp,
+  // version number, or any combination of this or other information, in an
+  // implementation-defined format.
+  optional string code_identifier = 4;
+
+  // The filename containing debugging information associated with the code
+  // module.  If debugging information is stored in a file separate from the
+  // code module itself (as is the case when .pdb or .dSYM files are used),
+  // this will be different from code_file.  If debugging information is
+  // stored in the code module itself (possibly prior to stripping), this
+  // will be the same as code_file.
+  optional string debug_file = 5;
+
+  // An identifying string similar to code_identifier, but identifies a
+  // specific version and build of the associated debug file.  This may be
+  // the same as code_identifier when the debug_file and code_file are
+  // identical or when the same identifier is used to identify distinct
+  // debug and code files.
+  optional string debug_identifier = 6;
+
+  // A human-readable representation of the code module's version.
+  optional string version = 7;
+}
+
+// The state of a thread.
+message ThreadState {
+  optional string thread_name = 1;
+}
+
+// The state of a process.
+message ProcessState {
+  repeated CodeModule modules = 1;
+  repeated ThreadState threads = 2;
+}
+
+// A stability report contains information relevant to Chrome's execution at a

[Sigurður Ásgeirsson, 2016/08/11 17:44:15]

I take this is intended to refer to a single logical instance of a "chrome
browser", e.g.  a process or a tree of processes that all are subordinates to a
single browser?

[manzagop (departed), 2016/08/12 21:23:22]

Correct. Clarified comment.

+// specific time.
+message StabilityReport {
+  optional SystemState system_state = 1;
+  repeated ProcessState process_states = 2;

[Sigurður Ásgeirsson, 2016/08/11 17:44:15]

I think if you want this to be useful for more than a single process at a time,
we need some indication of the type of each process and/or a hierarchical
relationship for the processes?
If that's a for later, maybe add a comment that this is currently intended only
for a single process, and/or a todo for extending the process state?

Things that'd be interesting to add to a process might include (chrome) process
type, start time, pid, parent pid, command line and so forth.

Also for chrome we specifically want experiment state, which I believe is a set
of {uint32_t, uint32_t } or some such. This probably wants to be a TODO, though,
as this implies more widely reaching changes?

[manzagop (departed), 2016/08/12 21:23:22]

Totally! This file is only a placeholder at this point. I plan to revise it in a
subsequent CL that fleshes out the contents of the stability report. There must
be no serialized version of it until that point.

I've sprinkled a few TODOs.

+}