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

skia/ext/SkDiscardableMemory_chrome.h

 // Copyright 2013 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_DISCARDABLE_MEMORY_CHROME_H_
 #define SKIA_EXT_SK_DISCARDABLE_MEMORY_CHROME_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "third_party/skia/src/core/SkDiscardableMemory.h"
 
 namespace base {
 class DiscardableMemory;
+
+namespace trace_event {
+class MemoryAllocatorDump;
+class ProcessMemoryDump;
 }
 
+}  // namespace base
+
 // This class implements the SkDiscardableMemory interface using
 // base::DiscardableMemory.
 class SK_API SkDiscardableMemoryChrome : public SkDiscardableMemory {
 public:
  ~SkDiscardableMemoryChrome() override;
 
   // SkDiscardableMemory:
  bool lock() override;
  void* data() override;
  void unlock() override;
 
+ base::trace_event::MemoryAllocatorDump* CreateMemoryAllocatorDump(
+     const char* name,
+     base::trace_event::ProcessMemoryDump* pmd) const;
+
 private:
   friend class SkDiscardableMemory;
 
   SkDiscardableMemoryChrome(scoped_ptr<base::DiscardableMemory> memory);
 
   scoped_ptr<base::DiscardableMemory> discardable_;
 };
 
 #endif  // SKIA_EXT_SK_DISCARDABLE_MEMORY_CHROME_H_