Add temporary DumpWithoutCrashing to understand why the filesystem URL origin checks are failing in

content/browser/child_process_security_policy_impl.cc

 // Copyright (c) 2012 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 "content/browser/child_process_security_policy_impl.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/command_line.h"
+#include "base/debug/dump_without_crashing.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/string_util.h"
 #include "build/build_config.h"
 #include "content/browser/site_instance_impl.h"
 #include "content/common/site_isolation_policy.h"
 #include "content/public/browser/child_process_data.h"
@@ skipping 773 matching lines @@
     const storage::FileSystemURL& filesystem_url,
     int permissions) {
   if (!filesystem_url.is_valid())
     return false;
 
   // If |filesystem_url.origin()| is not committable in this process, then this
   // page should not be able to place content in that origin via the filesystem
   // API either.
   if (!CanCommitURL(child_id, filesystem_url.origin())) {
     UMA_HISTOGRAM_BOOLEAN("FileSystem.OriginFailedCanCommitURL", true);
+    // TODO(nick): Temporary instrumentation for https://crbug.com/654479.
+    base::debug::DumpWithoutCrashing();

[nasko, 2016/10/10 21:45:09]

Should we capture the filesystem_url contents explicitly to ensure they are in
the dump? Or do we care mostly about the stack trace?

     return false;
   }
 
   if (filesystem_url.path().ReferencesParent())
     return false;
 
   // Any write access is disallowed on the root path.
   if (storage::VirtualPath::IsRootPath(filesystem_url.path()) &&
       (permissions & ~READ_FILE_GRANT)) {
     return false;
@@ skipping 162 matching lines @@
   base::AutoLock lock(lock_);
 
   SecurityStateMap::iterator state = security_state_.find(child_id);
   if (state == security_state_.end())
     return false;
 
   return state->second->can_send_midi_sysex();
 }
 
 }  // namespace content