[tracing] Improve the memory maps dumper generation format.

base/trace_event/process_memory_totals.h

Index: base/trace_event/process_memory_totals.h
diff --git a/base/trace_event/process_memory_totals.h b/base/trace_event/process_memory_totals.h
index ef0289ee3d8c643b99d492a31e40dff84b0eb98d..29c94c9aaccb6cc60bcc0d092c4bcbc52d938eff 100644
--- a/base/trace_event/process_memory_totals.h
+++ b/base/trace_event/process_memory_totals.h
@@ -13,7 +13,7 @@ namespace trace_event {
 
 class TracedValue;
 
-// Dump provider which collects process-wide memory stats.
+// Data model for process-wide memory stats.
 class BASE_EXPORT ProcessMemoryTotals {
  public:
   ProcessMemoryTotals() : resident_set_bytes_(0) {}