Reland of Change memory dumps to not use periodic dumps by default.

content/browser/tracing/tracing_ui.cc

Index: content/browser/tracing/tracing_ui.cc
diff --git a/content/browser/tracing/tracing_ui.cc b/content/browser/tracing/tracing_ui.cc
index 14389658a420ecb7b3f5d00d287fedeabee87753..7943d902f083f3e4044cf5f92b32e5397427a49e 100644
--- a/content/browser/tracing/tracing_ui.cc
+++ b/content/browser/tracing/tracing_ui.cc
@@ -89,6 +89,24 @@
   *trace_config = base::trace_event::TraceConfig(category_filter_string,
                                                  record_mode);
 
+  // When enabling memory-infra via tracing, use periodic dumping to trigger a
+  // detailed dump every 5s.
+  if (trace_config->IsCategoryGroupEnabled(
+          base::trace_event::MemoryDumpManager::kTraceCategory)) {
+    base::trace_event::TraceConfig::MemoryDumpConfig::Trigger trigger = {
+        5000,  // min_time_between_dumps_ms
+        base::trace_event::MemoryDumpLevelOfDetail::DETAILED,
+        base::trace_event::MemoryDumpType::PERIODIC_INTERVAL};
+    base::trace_event::TraceConfig::MemoryDumpConfig memory_dump_config;
+    memory_dump_config.triggers.push_back(trigger);
+
+    // TODO(ssid): Make a newly constructed MemoryDumpConfig use the default
+    // dump modes.
+    memory_dump_config.allowed_dump_modes.insert(
+        base::trace_event::MemoryDumpLevelOfDetail::DETAILED);
+    trace_config->ResetMemoryDumpConfig(memory_dump_config);
+  }
+
   bool enable_systrace;
   options_ok &= options->GetBoolean("useSystemTracing", &enable_systrace);
   if (enable_systrace)