BASELINE: Update Chromium to 67.0.3396.47

Change-Id: Idcb1341782e417561a2473eeecc82642dafda5b7
Reviewed-by: Michal Klocek <michal.klocek@qt.io>

1 files changed, 74 insertions, 0 deletions

diff --git a/chromium/third_party/blink/renderer/platform/heap/self_keep_alive.h b/chromium/third_party/blink/renderer/platform/heap/self_keep_alive.h
new file mode 100644
index 00000000000..5e60054db89
--- /dev/null
+++ b/chromium/third_party/blink/renderer/platform/heap/self_keep_alive.h
@@ -0,0 +1,74 @@
+// 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.
+
+#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_HEAP_SELF_KEEP_ALIVE_H_
+#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_HEAP_SELF_KEEP_ALIVE_H_
+
+#include "third_party/blink/renderer/platform/heap/persistent.h"
+#include "third_party/blink/renderer/platform/wtf/allocator.h"
+#include "third_party/blink/renderer/platform/wtf/assertions.h"
+
+namespace blink {
+
+// SelfKeepAlive<Object> is the idiom to use for objects that have to keep
+// themselves temporarily alive and cannot rely on there being some
+// external reference in that interval:
+//
+//  class Opener {
+//  public:
+//     ...
+//     void open()
+//     {
+//         // Retain a self-reference while in an open()ed state:
+//         m_keepAlive = this;
+//         ....
+//     }
+//
+//     void close()
+//     {
+//         // Clear self-reference that ensured we were kept alive while opened.
+//         m_keepAlive.clear();
+//         ....
+//     }
+//
+//  private:
+//     ...
+//     SelfKeepAlive m_keepAlive;
+//  };
+//
+// The responsibility to call clear() in a timely fashion resides with the
+// implementation of the object.
+//
+//
+template <typename Self>
+class SelfKeepAlive final {
+  DISALLOW_NEW();
+
+ public:
+  SelfKeepAlive() = default;
+
+  explicit SelfKeepAlive(Self* self) { Assign(self); }
+
+  SelfKeepAlive& operator=(Self* self) {
+    Assign(self);
+    return *this;
+  }
+
+  void Clear() { keep_alive_.Clear(); }
+
+  explicit operator bool() const { return keep_alive_; }
+
+ private:
+  void Assign(Self* self) {
+    DCHECK(!keep_alive_ || keep_alive_.Get() == self);
+    keep_alive_ = self;
+  }
+
+  GC_PLUGIN_IGNORE("420515")
+  Persistent<Self> keep_alive_;
+};
+
+}  // namespace blink
+
+#endif  // THIRD_PARTY_BLINK_RENDERER_PLATFORM_HEAP_SELF_KEEP_ALIVE_H_