[tracing] Display the resident size of the discardable memory segments

base/trace_event/process_memory_dump.h

Index: base/trace_event/process_memory_dump.h
diff --git a/base/trace_event/process_memory_dump.h b/base/trace_event/process_memory_dump.h
index da18a14b1ca1d2909224011fcb5bc89d0286b69e..3338c7eaeec63360b674ddc1a81c9c53c84c80f3 100644
--- a/base/trace_event/process_memory_dump.h
+++ b/base/trace_event/process_memory_dump.h
@@ -120,6 +120,12 @@ class BASE_EXPORT ProcessMemoryDump {
   // Called at trace generation time to populate the TracedValue.
   void AsValueInto(TracedValue* value) const;
 
+  // Returns the total bytes resident for a memory segment, with given
+  // |start_address| and |mapped_size|. |mapped_size| is specified in bytes. The
+  // value returned is valid only if the given range is currently mmapped by the
+  // process. Returns -1 if counting is not implemented in the current platform.
+  static ssize_t CountResidentBytes(void* start_address, size_t mapped_size);

[Primiano Tucci (use gerrit), 2015/10/06 17:14:09]

IIRC static methods should be declared before non statics. Move this up.

[ssid, 2015/10/07 09:13:19]

Done.

+
   ProcessMemoryTotals* process_totals() { return &process_totals_; }
   bool has_process_totals() const { return has_process_totals_; }
   void set_has_process_totals() { has_process_totals_ = true; }