memory-infra: Fill the memory dump callback result (1/2)

base/trace_event/memory_allocator_dump.h

Index: base/trace_event/memory_allocator_dump.h
diff --git a/base/trace_event/memory_allocator_dump.h b/base/trace_event/memory_allocator_dump.h
index c781f071bba40ab08c25dcb18ec1f59fc1b1fc12..6a26445b9ac45cf8e6eefb20c1b7ba0908861cb8 100644
--- a/base/trace_event/memory_allocator_dump.h
+++ b/base/trace_event/memory_allocator_dump.h
@@ -63,6 +63,10 @@ class BASE_EXPORT MemoryAllocatorDump {
   void AddScalarF(const char* name, const char* units, double value);
   void AddString(const char* name, const char* units, const std::string& value);
 
+  // Get the size for this dump.
+  // The size is the value set with AddScalar(kNameSize, kUnitsBytes, size);
+  uint64_t GetSize();

[Primiano Tucci (use gerrit), 2017/03/22 17:19:52]

can you plz:
- make this private (or protected, if it helps from a documentation viewpoint)
- make MDM a friend of this class
- Add a TODO(hjd) explaining that this is transitional, untile we get to the
state where the full PMD can be sent over IPC/MOJO (better if you file a bug
explaining this and link it to the todo) 

[hjd, 2017/03/22 19:24:20]

Done.

+
   // Absolute name, unique within the scope of an entire ProcessMemoryDump.
   const std::string& absolute_name() const { return absolute_name_; }
 
@@ -90,6 +94,7 @@ class BASE_EXPORT MemoryAllocatorDump {
   std::unique_ptr<TracedValue> attributes_;
   MemoryAllocatorDumpGuid guid_;
   int flags_;  // See enum Flags.
+  uint64_t size_;
 
   // A local buffer for Sprintf conversion on fastpath. Avoids allocating
   // temporary strings on each AddScalar() call.