[bgmode] Log the unpin stack trace to Crash Keys

blimp/engine/app/blimp_engine_crash_keys.cc

 // 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.
 
 #include "blimp/engine/app/blimp_engine_crash_keys.h"
 
 #include "base/debug/crash_logging.h"
 #include "base/macros.h"
 #include "components/crash/core/common/crash_keys.h"
 
 namespace blimp {
 namespace engine {
 
 size_t RegisterEngineCrashKeys() {
   // For now these need to be kept relatively up to date with those in
   // //chrome/common/crash_keys.cc::RegisterChromeCrashKeys()
   // All of the keys used in //content and //components/crash must show up
   // here.
   // TODO(marcinjb): Change the approach when http://crbug.com/598854 is
   // resolved.
   const base::debug::CrashKey engine_keys[] = {
       { crash_keys::kClientId, crash_keys::kSmallSize },
       { crash_keys::kChannel, crash_keys::kSmallSize },
       { crash_keys::kNumVariations, crash_keys::kSmallSize },
       { crash_keys::kVariations, crash_keys::kLargeSize },
 
       // browser/:
+      { "browser-unpin-trace", crash_keys::kMediumSize},
       { "third-party-modules-loaded", crash_keys::kSmallSize },
       { "third-party-modules-not-loaded", crash_keys::kSmallSize },
       { "enrolled-to-domain", crash_keys::kSmallSize },
 
       // //content crash keys
       { "bad_message_reason", crash_keys::kSmallSize },
       { "channel_error_bt", crash_keys::kMediumSize },
       { "discardable-memory-allocated", crash_keys::kSmallSize },
       { "discardable-memory-free", crash_keys::kSmallSize },
       { "mojo-message-error", crash_keys::kMediumSize },
@@ skipping 74 matching lines @@
       { "swdh_set_hosted_version_worker_pid", crash_keys::kSmallSize },
       { "swdh_set_hosted_version_host_pid", crash_keys::kSmallSize },
     };
 
   return base::debug::InitCrashKeys(engine_keys, arraysize(engine_keys),
                                     crash_keys::kChunkMaxLength);
 }
 
 }  // namespace engine
 }  // namespace blimp