Update from https://crrev.com/333737

base/trace_event/process_memory_totals_dump_provider.cc

Index: base/trace_event/process_memory_totals_dump_provider.cc
diff --git a/base/trace_event/process_memory_totals_dump_provider.cc b/base/trace_event/process_memory_totals_dump_provider.cc
index 06b537c4188ada9420ae05c41064e5b8e4602100..37f9bed68c9b2b4e59e8b83b70fc776c5117906a 100644
--- a/base/trace_event/process_memory_totals_dump_provider.cc
+++ b/base/trace_event/process_memory_totals_dump_provider.cc
@@ -8,6 +8,17 @@
 #include "base/trace_event/process_memory_dump.h"
 #include "base/trace_event/process_memory_totals.h"
 
+#if defined(OS_LINUX) || defined(OS_ANDROID)
+#include <fcntl.h>
+
+#include "base/files/file_util.h"
+
+namespace {
+bool kernel_supports_rss_peak_reset = true;
+const char kClearPeakRssCommand[] = "5";
+}
+#endif
+
 namespace base {
 namespace trace_event {
 
@@ -47,8 +58,30 @@ bool ProcessMemoryTotalsDumpProvider::OnMemoryDump(ProcessMemoryDump* pmd) {
                                ? rss_bytes_for_testing
                                : process_metrics_->GetWorkingSetSize();
 
+  uint64 peak_rss_bytes = 0;
+
+#if !defined(OS_IOS)
+  peak_rss_bytes = process_metrics_->GetPeakWorkingSetSize();
+#if defined(OS_LINUX) || defined(OS_ANDROID)
+  if (kernel_supports_rss_peak_reset) {
+    // TODO(ssid): Fix crbug.com/461788 to write to the file from sandboxed
+    // processes.
+    int clear_refs_fd = open("/proc/self/clear_refs", O_WRONLY);
+    if (clear_refs_fd > 0 &&
+        WriteFileDescriptor(clear_refs_fd, kClearPeakRssCommand,
+                            sizeof(kClearPeakRssCommand))) {
+      pmd->process_totals()->set_is_peak_rss_resetable(true);
+    } else {
+      kernel_supports_rss_peak_reset = false;
+    }
+    close(clear_refs_fd);
+  }
+#endif  // defined(OS_LINUX) || defined(OS_ANDROID)
+#endif  // !defined(OS_IOS)
+
   if (rss_bytes > 0) {
     pmd->process_totals()->set_resident_set_bytes(rss_bytes);
+    pmd->process_totals()->set_peak_resident_set_bytes(peak_rss_bytes);
     pmd->set_has_process_totals();
     return true;
   }