Adding v8_isolate_memory_dump_provider.

gin/v8_isolate_memory_dump_provider.h

+// 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_V8_ISOLATE_MEMORY_DUMP_PROVIDER_H_
+#define GIN_V8_ISOLATE_MEMORY_DUMP_PROVIDER_H_
+
+#include "base/trace_event/memory_dump_provider.h"
+#include "gin/gin_export.h"
+
+namespace gin {
+
+class IsolateHolder;
+
+// Memory dump provider for the chrome://tracing infrastructure. It dumps
+// summarized memory stats about the V8 Isolates.

[rmcilroy, 2015/04/21 21:57:26]

nit /s/the V8 Isolates/a V8 isolate/

[ssid, 2015/04/22 10:41:35]

Isn't it like soon we are going to have multiple isolates per thread?

[rmcilroy, 2015/04/22 15:41:05]

No, there is only ever a single isolate per thread generally.

In any case, it doesn't matter - each V8IsolateMemoryDumpProvider only dumps
memory for a single isolate - even if there are multiple isolates per thread
each would have a separate V8IsolateMemoryDumpProvider.

+class V8IsolateMemoryDumpProvider
+    : public base::trace_event::MemoryDumpProvider {
+ public:
+  explicit V8IsolateMemoryDumpProvider(IsolateHolder* isolate_holder);
+  ~V8IsolateMemoryDumpProvider() override;
+
+  // MemoryDumpProvider implementation.
+  bool DumpInto(base::trace_event::ProcessMemoryDump* pmd) override;
+  const char* GetFriendlyName() const override;
+
+ private:
+  IsolateHolder* isolate_holder_;  // Not owned (IsolateHolder owns this).

[rmcilroy, 2015/04/21 21:57:26]

IsolateHolder doesn't own itself. Just drop the "(IsolateHolder owns this)"

[ssid, 2015/04/22 10:41:35]

Done.

+
+  DISALLOW_COPY_AND_ASSIGN(V8IsolateMemoryDumpProvider);
+};
+
+}  // namespace gin
+
+#endif  // GIN_V8_ISOLATE_MEMORY_DUMP_PROVIDER_H_