[tracing] Sanitize process memory dumps for background mode

base/trace_event/memory_allocator_dump.cc

Index: base/trace_event/memory_allocator_dump.cc
diff --git a/base/trace_event/memory_allocator_dump.cc b/base/trace_event/memory_allocator_dump.cc
index f9b5799c05eb04b388e37dd6d7858d554990a65a..56470d800af8a8374f65b38d6f8a8144733b01a5 100644
--- a/base/trace_event/memory_allocator_dump.cc
+++ b/base/trace_event/memory_allocator_dump.cc
@@ -80,6 +80,12 @@ void MemoryAllocatorDump::AddScalarF(const char* name,
 void MemoryAllocatorDump::AddString(const char* name,
                                     const char* units,
                                     const std::string& value) {
+  // String attributes are disabled in background mode.
+  if (process_memory_dump_->level_of_detail() ==
+      MemoryDumpLevelOfDetail::BACKGROUND) {

[Primiano Tucci (use gerrit), 2016/05/27 17:23:35]

I wonder if we want also a NOTREACHED() here so we can detect if somebody is
wasting time pushing strings that are dropped on the floor in tests.

[ssid, 2016/05/31 22:33:20]

Done.

+    return;
+  }
+
   attributes_->BeginDictionary(name);
   attributes_->SetString("type", kTypeString);
   attributes_->SetString("units", units);