[tracing] Add SkResourceCache statistics to chrome://tracing (chrome side)

skia/ext/SkTraceMemoryDump_chrome.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 SKIA_EXT_SK_TRACE_MEMORY_DUMP_CHROME_H_
+#define SKIA_EXT_SK_TRACE_MEMORY_DUMP_CHROME_H_
+
+#include "base/macros.h"
+#include "third_party/skia/include/core/SkTraceMemoryDump.h"
+
+namespace base {
+namespace trace_event {
+class MemoryAllocatorDump;
+class ProcessMemoryDump;
+}
+}
+
+namespace skia {
+
+class SkTraceMemoryDump_Chrome : public SkTraceMemoryDump {
+ public:
+  // This should never outlive the OnMemoryDump call since the
+  // ProcessMemoryDump is valid only in that timefrace.
+  SkTraceMemoryDump_Chrome(
+      base::trace_event::ProcessMemoryDump* process_memory_dump);
+  ~SkTraceMemoryDump_Chrome() override;
+
+  // SkTraceMemoryDump implementation:
+  void dumpNumericValue(const char* dumpName,
+                        const char* valueName,
+                        const char* units,
+                        uint64_t value) override;
+  void setMemoryBacking(const char* dumpName,
+                        const char* backingType,
+                        const char* backingObjectId) override;
+  void setDiscardableMemoryBacking(
+      const char* dumpName,
+      const SkDiscardableMemory& discardableMemoryObject) override;
+
+ private:
+  base::trace_event::ProcessMemoryDump* process_memory_dump_;

[ericrk, 2015/08/26 18:12:06]

As I think subclassing will lead to the most sane approach here, can you add a
protected getter for this? I can also add this in my future CL.

+
+  // Helper to create allocator dumps.
+  base::trace_event::MemoryAllocatorDump* GetOrCreateAllocatorDump(
+      const char* dumpName);
+
+  DISALLOW_COPY_AND_ASSIGN(SkTraceMemoryDump_Chrome);
+};
+
+}  // namespace skia
+
+#endif  // SKIA_EXT_SK_TRACE_MEMORY_DUMP_CHROME_H_