Generate dumps for relevant renderers when users kill a hung pepper plugin.

ppapi/shared_impl/ppapi_message_tracker.h

Index: ppapi/shared_impl/ppapi_message_tracker.h
diff --git a/ppapi/shared_impl/ppapi_message_tracker.h b/ppapi/shared_impl/ppapi_message_tracker.h
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+// 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.
+
+#ifndef PPAPI_SHARED_IMPL_PPAPI_MESSAGE_TRACKER_H_
+#define PPAPI_SHARED_IMPL_PPAPI_MESSAGE_TRACKER_H_
+
+#include "base/basictypes.h"
+#include "base/synchronization/lock.h"
+#include "ppapi/shared_impl/ppapi_shared_export.h"
+
+template <typename T> struct DefaultSingletonTraits;
+
+namespace ppapi {
+
+// PpapiMessageTracker uses a counter to record whether anyone is sending or
+// receiving pepper messages in the current process.
+// This class is thread safe.
+class PPAPI_SHARED_EXPORT PpapiMessageTracker {
+ public:
+  static PpapiMessageTracker* GetInstance();
+
+  void EnterMessageHandling();
+  void ExitMessageHandling();
+  bool IsHandlingMessage();
+
+ private:
+  friend struct DefaultSingletonTraits<PpapiMessageTracker>;
+
+  PpapiMessageTracker();
+  ~PpapiMessageTracker();
+
+  base::Lock lock_;
+  int enter_count_;
+
+  DISALLOW_COPY_AND_ASSIGN(PpapiMessageTracker);
+};
+
+class PPAPI_SHARED_EXPORT ScopedTrackPpapiMessage {
+ public:
+  ScopedTrackPpapiMessage();
+  ~ScopedTrackPpapiMessage();
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ScopedTrackPpapiMessage);
+};
+
+}  // namespace ppapi
+
+#endif  // PPAPI_SHARED_IMPL_PPAPI_MESSAGE_TRACKER_H_