Fix the size dumped by child discardable manager for tracing.

content/common/discardable_shared_memory_heap.cc

Index: content/common/discardable_shared_memory_heap.cc
diff --git a/content/common/discardable_shared_memory_heap.cc b/content/common/discardable_shared_memory_heap.cc
index 8996979a730afc1e252de45557bf3acf0574e038..f1990ba99cf9519f3607da2da11c5662a2396413 100644
--- a/content/common/discardable_shared_memory_heap.cc
+++ b/content/common/discardable_shared_memory_heap.cc
@@ -74,10 +74,11 @@ DiscardableSharedMemoryHeap::ScopedMemorySegment::CreateMemoryAllocatorDump(
   base::trace_event::MemoryAllocatorDump* dump = pmd->CreateAllocatorDump(name);
   dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameSize,
                   base::trace_event::MemoryAllocatorDump::kUnitsBytes,
-                  static_cast<uint64_t>(span->length()));
+                  static_cast<uint64_t>(span->shared_memory()->mapped_size()));

[reveman, 2015/08/26 15:56:18]

hm, mapped_size is the total size of the segment but we're creating a dump just
for the span, right? Should this not be "span->length() * block_size" ?

[ssid, 2015/08/26 16:00:35]

Ah yes, I got confused here because of the host side. Thanks

 
-  pmd->AddSuballocation(dump->guid(),
-                        base::StringPrintf("discardable/segment_%d", id_));
+  pmd->AddSuballocation(
+      dump->guid(),
+      base::StringPrintf("discardable/segment_%d/allocated_objects", id_));
   return dump;
 }