mash: Store chrome --mash crash key metadata in shared memory

chrome/app/mash/mash_runner.cc

Index: chrome/app/mash/mash_runner.cc
diff --git a/chrome/app/mash/mash_runner.cc b/chrome/app/mash/mash_runner.cc
index d5086ec61003d95db27dc5df9b8bf95cdd6fc551..9f750b40685ef85bb8b45eced983e21775ebb70f 100644
--- a/chrome/app/mash/mash_runner.cc
+++ b/chrome/app/mash/mash_runner.cc
@@ -56,6 +56,10 @@
 #include "ui/base/ui_base_paths.h"
 #include "ui/base/ui_base_switches.h"
 
+#if defined(OS_CHROMEOS)
+#include "chrome/app/mash/mash_crash_keys.h"
+#endif  // defined(OS_CHROMEOS)
+
 using service_manager::mojom::ServiceFactory;
 
 namespace {
@@ -145,9 +149,20 @@ void OnInstanceQuitInMain(base::RunLoop* run_loop,
 
 }  // namespace
 
-MashRunner::MashRunner() {}
+MashRunner::MashRunner() {
+#if defined(OS_CHROMEOS)
+  // NOTE: On Chrome OS, crash reporting for the root process and non-browser
+  // service processes is handled by the OS-level crash_reporter, not in-process
+  // breakpad. It therefore uses its own crash key implementation.
+  mash_crash_keys::Initialize();

[hashimoto, 2017/03/02 07:42:23]

How about putting this code in MashMain or RunMain to be consistent with other
initialization code?

+#endif
+}
 
-MashRunner::~MashRunner() {}
+MashRunner::~MashRunner() {

[hashimoto, 2017/03/02 07:42:23]

ditto.
Other shutdown code is in RunMain().

+#if defined(OS_CHROMEOS)
+  mash_crash_keys::Shutdown();
+#endif
+}
 
 int MashRunner::Run() {
   base::TaskScheduler::CreateAndSetSimpleTaskScheduler(
@@ -257,8 +272,6 @@ int MashMain() {
 #if !defined(OFFICIAL_BUILD)
   // Initialize stack dumping before initializing sandbox to make sure symbol
   // names in all loaded libraries will be cached.
-  // NOTE: On Chrome OS, crash reporting for the root process and non-browser
-  // service processes is handled by the OS-level crash_reporter.

[hashimoto, 2017/03/02 07:42:23]

IMO we still need this comment here to describe how stack dumping works on
Chrome OS.

   base::debug::EnableInProcessStackDumping();
 #endif