Adding v8_isolate_memory_dump_provider.

gin/v8_isolate_memory_dump_provider.h

Index: gin/v8_isolate_memory_dump_provider.h
diff --git a/gin/v8_isolate_memory_dump_provider.h b/gin/v8_isolate_memory_dump_provider.h
new file mode 100644
index 0000000000000000000000000000000000000000..16be579633ca3ed74c2bd041621a4d09905cb720
--- /dev/null
+++ b/gin/v8_isolate_memory_dump_provider.h
@@ -0,0 +1,40 @@
+// Copyright 2015 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 GIN_PUBLIC_V8_ISOLATE_MEMORY_DUMP_PROVIDER_H_

[Primiano Tucci (use gerrit), 2015/04/17 19:10:31]

Fix this (remove PUBLIC)

+#define GIN_PUBLIC_V8_ISOLATE_MEMORY_DUMP_PROVIDER_H_
+
+#include <istream>

[Primiano Tucci (use gerrit), 2015/04/17 19:10:31]

I don't think you need this

+
+#include "base/memory/scoped_ptr.h"

[Primiano Tucci (use gerrit), 2015/04/17 19:10:31]

don't need this either

+#include "base/trace_event/memory_dump_manager.h"

[Primiano Tucci (use gerrit), 2015/04/17 19:10:31]

Neither this. 

+#include "base/trace_event/memory_dump_provider.h"
+#include "gin/gin_export.h"
+
+namespace gin {
+
+class IsolateHolder;
+
+// Dump provider which collects process-wide memory stats.

[Primiano Tucci (use gerrit), 2015/04/17 19:10:31]

I'd probably word this as:
// Memory dump provider for the chrome://tracing infrastructure. It dumps
summarized memory stats about the V8 Isolates.

+class V8IsolateMemoryDumpProvider
+    : public base::trace_event::MemoryDumpProvider {
+ public:
+  V8IsolateMemoryDumpProvider(IsolateHolder* isolate_holder);
+  ~V8IsolateMemoryDumpProvider() override;
+
+  // MemoryDumpProvider implementation.
+  bool DumpInto(base::trace_event::ProcessMemoryDump* pmd) override;
+  const char* GetFriendlyName() const override;
+
+ private:
+  // This object is not owned by the IsolateHolder whose reference
+  // is stored in this member.
+  IsolateHolder* isolate_holder_;

[Primiano Tucci (use gerrit), 2015/04/17 19:10:31]

It is sufficient to say:
IsolateHolder* isolate_holder_;  // Not owned.

+
+  DISALLOW_COPY_AND_ASSIGN(V8IsolateMemoryDumpProvider);
+};
+
+}  // namespace gin
+
+#endif  // GIN_PUBLIC_V8_ISOLATE_MEMORY_DUMP_PROVIDER_H_