[tracing] Dump child processes' memory metrics in browser

components/tracing/BUILD.gn

Index: components/tracing/BUILD.gn
diff --git a/components/tracing/BUILD.gn b/components/tracing/BUILD.gn
index 40e90f9def043251a2f5c6d0c676ed5231d1af1f..58e5c722de3ef82c8169fea685bb0be8079bd73e 100644
--- a/components/tracing/BUILD.gn
+++ b/components/tracing/BUILD.gn
@@ -10,6 +10,8 @@ component("tracing") {
     "child_trace_message_filter.h",
     "graphics_memory_dump_provider_android.cc",
     "graphics_memory_dump_provider_android.h",
+    "process_metrics_memory_dump_provider.cc",
+    "process_metrics_memory_dump_provider.h",
     "tracing_export.h",
     "tracing_messages.cc",
     "tracing_messages.h",
@@ -21,6 +23,10 @@ component("tracing") {
     "//base",
     "//ipc",
   ]
+
+  if (is_linux || is_android) {
+    sources += [ "process_metrics_memory_dump_provider_posix.cc" ]
+  }
 }
 
 component("startup_tracing") {
@@ -44,6 +50,7 @@ source_set("unit_tests") {
 
   sources = [
     "graphics_memory_dump_provider_android_unittest.cc",
+    "process_metrics_memory_dump_provider_unittest.cc",
   ]
 
   deps = [