Deal gracefully with removing content settings for unregistered extensions.

chrome/browser/extensions/api/content_settings/content_settings_store.cc

Index: chrome/browser/extensions/api/content_settings/content_settings_store.cc
diff --git a/chrome/browser/extensions/api/content_settings/content_settings_store.cc b/chrome/browser/extensions/api/content_settings/content_settings_store.cc
index 84408d99a29a9892d27644a4f02c53fd71cf54f0..802cac95b780e4fc4e1829d0c2872a9ef99258d0 100644
--- a/chrome/browser/extensions/api/content_settings/content_settings_store.cc
+++ b/chrome/browser/extensions/api/content_settings/content_settings_store.cc
@@ -235,8 +235,8 @@ void ContentSettingsStore::ClearContentSettingsForExtension(
       char ext_id_buffer[33];
       base::strlcpy(ext_id_buffer, ext_id.c_str(), sizeof(ext_id_buffer));
       base::debug::Alias(ext_id_buffer);
-      // Do a clean crash.
-      CHECK(false);
+      // Gracefully return instead of crashing below.
+      return;
     }
     notify = !map->empty();
     map->clear();