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

base/trace_event/memory_dump_manager.cc

Index: base/trace_event/memory_dump_manager.cc
diff --git a/base/trace_event/memory_dump_manager.cc b/base/trace_event/memory_dump_manager.cc
index d1025c1215a68ef8127f70ca7de1e362c6667cc0..489e4191381e1bf35c0415fd2b2d5cb3c64c3774 100644
--- a/base/trace_event/memory_dump_manager.cc
+++ b/base/trace_event/memory_dump_manager.cc
@@ -92,6 +92,15 @@ void OnGlobalDumpDone(MemoryDumpCallback wrapped_callback,
   }
 }
 
+void FillOsDumpFromProcessMemoryDump(
+    MemoryDumpCallbackResult::OSMemDump& osDump,

[Primiano Tucci (use gerrit), 2017/04/03 08:49:27]

output arguments should:
1. use pointers, not references. references can be used only for input.
Specifically our style guide says:
"All parameters passed by reference must be labeled const." [1]
2. be at the end of the argument list "When ordering function parameters, put
all input-only parameters before any output parameters." [2]

On top of this, when you pass input arguments as pointers, I find "const" to
still help readability
Also variables/args should be lower_with_under [3] (osDump -> os_dump)

so this should be:
FillOsDumpFromProcessMemoryDump(const ProcessMemoryDump* pmd,
MemoryDumpCallbackResult::OSMemDump* os_dump) {
...
}


[1] https://google.github.io/styleguide/cppguide.html#Reference_Arguments
[2]
https://google.github.io/styleguide/cppguide.html#Function_Parameter_Ordering
[3] https://google.github.io/styleguide/cppguide.html#Variable_Names

+    ProcessMemoryDump* pmd) {
+  if (pmd->has_process_totals()) {
+    auto* totals = pmd->process_totals();

[Primiano Tucci (use gerrit), 2017/04/03 08:49:27]

minor thing about "auto". There are no official rules on this, but my rule of
thumb is that if the explicit type fits still in one line (80 cols) I find the
overall code more readable / codesearcheable. Here I'd do

const ProcessMemoryTotals* totals = pmd->process_totals();

+    osDump.resident_set_kb = totals->resident_set_bytes() / 1024;
+  }
+}
+
 // Proxy class which wraps a ConvertableToTraceFormat owned by the
 // |session_state| into a proxy object that can be added to the trace event log.
 // This is to solve the problem that the MemoryDumpSessionState is refcounted
@@ -798,6 +807,10 @@ void MemoryDumpManager::FinalizeDumpAndAddToTrace(
           GetDumpsSumKb("partition_alloc/partitions/*", process_memory_dump);
       result.chrome_dump.blink_gc_total_kb =
           GetDumpsSumKb("blink_gc", process_memory_dump);
+      FillOsDumpFromProcessMemoryDump(result.os_dump, process_memory_dump);
+    } else {
+      auto& os_dump = result.extra_processes_dump[pid];
+      FillOsDumpFromProcessMemoryDump(os_dump, process_memory_dump);
     }
   }