Add possibility to ignore unregistered crash keys. Use this from WebView

android_webview/common/crash_reporter/crash_keys.cc

 // Copyright 2017 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 "android_webview/common/crash_reporter/crash_keys.h"
 
 #include "base/debug/crash_logging.h"
 #include "components/crash/core/common/crash_keys.h"
 
 using namespace crash_keys;
@@ skipping 19 matching lines @@
     { "bad_message_reason", kSmallSize },
     { "discardable-memory-allocated", kSmallSize },
     { "discardable-memory-free", kSmallSize },
     { "mojo-message-error", kMediumSize },
     { "total-discardable-memory-allocated", kSmallSize },
   };
 
   std::vector<base::debug::CrashKey> keys(fixed_keys,
                                           fixed_keys + arraysize(fixed_keys));
 
-  return base::debug::InitCrashKeys(&keys.at(0), keys.size(), kChunkMaxLength);
+  return base::debug::InitCrashKeys(&keys.at(0), keys.size(), kChunkMaxLength,
+                                    true /* ignore_unregistered_keys */);
 }
 }
 
 }  // namespace crash_keys