Revert of [tracing] Dump child processes' memory metrics in browser

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
new file mode 100644
index 0000000000000000000000000000000000000000..1713ebf0bc99edd9b964bf66af8c2bfd8fd354b8
--- /dev/null
+++ b/base/trace_event/process_memory_totals_dump_provider.cc
@@ -0,0 +1,92 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/trace_event/process_memory_totals_dump_provider.h"
+
+#include <stddef.h>
+
+#include "base/process/process_metrics.h"
+#include "base/trace_event/process_memory_dump.h"
+#include "base/trace_event/process_memory_totals.h"
+#include "build/build_config.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 {
+
+// static
+uint64_t ProcessMemoryTotalsDumpProvider::rss_bytes_for_testing = 0;
+
+// static
+ProcessMemoryTotalsDumpProvider*
+ProcessMemoryTotalsDumpProvider::GetInstance() {
+  return Singleton<
+      ProcessMemoryTotalsDumpProvider,
+      LeakySingletonTraits<ProcessMemoryTotalsDumpProvider>>::get();
+}
+
+ProcessMemoryTotalsDumpProvider::ProcessMemoryTotalsDumpProvider()
+    : process_metrics_(ProcessMetrics::CreateCurrentProcessMetrics()) {}
+
+ProcessMemoryTotalsDumpProvider::~ProcessMemoryTotalsDumpProvider() {
+}
+
+// Called at trace dump point time. Creates a snapshot the memory counters for
+// the current process.
+bool ProcessMemoryTotalsDumpProvider::OnMemoryDump(const MemoryDumpArgs& args,
+                                                   ProcessMemoryDump* pmd) {
+  const uint64_t rss_bytes = rss_bytes_for_testing
+                                 ? rss_bytes_for_testing
+                                 : process_metrics_->GetWorkingSetSize();
+
+  uint64_t 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);
+  }
+#elif defined(OS_MACOSX)
+  size_t private_bytes;
+  bool res = process_metrics_->GetMemoryBytes(&private_bytes,
+                                              nullptr /* shared_bytes */);
+  if (res) {
+    pmd->process_totals()->SetExtraFieldInBytes("private_bytes", private_bytes);
+  }
+#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;
+  }
+
+  return false;
+}
+
+}  // namespace trace_event
+}  // namespace base