[tracing] Add SkResourceCache as suballocation to avoid double counting.

content/common/discardable_shared_memory_heap.h

Index: content/common/discardable_shared_memory_heap.h
diff --git a/content/common/discardable_shared_memory_heap.h b/content/common/discardable_shared_memory_heap.h
index 7ded677c3cc75630b61181c16a4b20258943550e..11d1cc7d351e13bd5cacb4d2959ef0ac466f4222 100644
--- a/content/common/discardable_shared_memory_heap.h
+++ b/content/common/discardable_shared_memory_heap.h
@@ -88,6 +88,11 @@ class CONTENT_EXPORT DiscardableSharedMemoryHeap {
   // Dumps memory statistics for chrome://tracing.
   bool OnMemoryDump(base::trace_event::ProcessMemoryDump* pmd);
 
+  // Creates a common dump for all sub-allocated objects from discardable
+  // memory.
+  static void CreateAllocatedObjectsDump(

[reveman, 2015/07/30 16:00:59]

I think this should be moved to the allocator implementation instead. See my
other comment.

[ssid, 2015/07/30 20:05:15]

I think it is needed in both implementations, so better to have it in base?

+      base::trace_event::ProcessMemoryDump* pmd);

[reveman, 2015/07/29 18:32:11]

why do we want a common dump? Would it not be more correct to have each
discardable memory sub-allocation be associated with the specific segment they
are part of?

[ssid, 2015/07/29 19:36:22]

Replied for the other comment.

+
   // Returns a unique identifier for a given tuple of (process id, segment id)
   // that can be used to match memory dumps across different processes.
   static base::trace_event::MemoryAllocatorDumpGuid GetSegmentGUIDForTracing(