Collect unclean shutdown debug information

base/debug/activity_analyzer.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 "base/debug/activity_analyzer.h"
 
+#include <utility>
+
 #include "base/files/file.h"
 #include "base/files/file_path.h"
 #include "base/files/memory_mapped_file.h"
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "base/stl_util.h"
 #include "base/strings/string_util.h"
 
 namespace base {
 namespace debug {
@@ skipping 18 matching lines @@
 GlobalActivityAnalyzer::GlobalActivityAnalyzer(
     std::unique_ptr<PersistentMemoryAllocator> allocator)
     : allocator_(std::move(allocator)), allocator_iterator_(allocator_.get()) {}
 
 GlobalActivityAnalyzer::~GlobalActivityAnalyzer() {}
 
 #if !defined(OS_NACL)
 std::unique_ptr<GlobalActivityAnalyzer> GlobalActivityAnalyzer::CreateWithFile(
     const FilePath& file_path) {
   std::unique_ptr<MemoryMappedFile> mmfile(new MemoryMappedFile());
-  mmfile->Initialize(file_path);
+  // Note: write access is required for snapshotting, which writes a sentinel to
+  // ensure the snapshot's consistency.
+  mmfile->Initialize(file_path, MemoryMappedFile::READ_WRITE);
   if (!mmfile->IsValid())
     return nullptr;
 
   if (!FilePersistentMemoryAllocator::IsFileAcceptable(*mmfile, true))
     return nullptr;
 
   return WrapUnique(new GlobalActivityAnalyzer(
              WrapUnique(new FilePersistentMemoryAllocator(
                             std::move(mmfile), 0, 0, base::StringPiece(),
                             true))));
@@ skipping 61 matching lines @@
     // Add this analyzer to the map of known ones, indexed by a unique thread
     // identifier.
     DCHECK(!ContainsKey(analyzers_, analyzer->GetThreadKey()));
     analyzer->allocator_reference_ = ref;
     analyzers_[analyzer->GetThreadKey()] = std::move(analyzer);
   }
 }
 
 }  // namespace debug
 }  // namespace base