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

base/trace_event/process_memory_maps_dump_provider.cc

Index: base/trace_event/process_memory_maps_dump_provider.cc
diff --git a/base/trace_event/process_memory_maps_dump_provider.cc b/base/trace_event/process_memory_maps_dump_provider.cc
new file mode 100644
index 0000000000000000000000000000000000000000..4c3959fe9be57f861777fb968a5704142efe66f0
--- /dev/null
+++ b/base/trace_event/process_memory_maps_dump_provider.cc
@@ -0,0 +1,176 @@
+// 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_maps_dump_provider.h"
+
+#include <stdint.h>
+
+#include "base/files/scoped_file.h"
+#include "base/format_macros.h"
+#include "base/logging.h"
+#include "base/strings/string_util.h"
+#include "base/trace_event/process_memory_dump.h"
+#include "base/trace_event/process_memory_maps.h"
+
+namespace base {
+namespace trace_event {
+
+// static
+FILE* ProcessMemoryMapsDumpProvider::proc_smaps_for_testing = nullptr;
+
+namespace {
+
+const uint32_t kMaxLineSize = 4096;
+
+bool ParseSmapsHeader(const char* header_line,
+                      ProcessMemoryMaps::VMRegion* region) {
+  // e.g., "00400000-00421000 r-xp 00000000 fc:01 1234  /foo.so\n"
+  bool res = true;  // Whether this region should be appended or skipped.
+  uint64_t end_addr = 0;
+  char protection_flags[5] = {0};
+  char mapped_file[kMaxLineSize];
+
+  if (sscanf(header_line, "%" SCNx64 "-%" SCNx64 " %4c %*s %*s %*s%4095[^\n]\n",
+             &region->start_address, &end_addr, protection_flags,
+             mapped_file) != 4)
+    return false;
+
+  if (end_addr > region->start_address) {
+    region->size_in_bytes = end_addr - region->start_address;
+  } else {
+    // This is not just paranoia, it can actually happen (See crbug.com/461237).
+    region->size_in_bytes = 0;
+    res = false;
+  }
+
+  region->protection_flags = 0;
+  if (protection_flags[0] == 'r') {
+    region->protection_flags |=
+        ProcessMemoryMaps::VMRegion::kProtectionFlagsRead;
+  }
+  if (protection_flags[1] == 'w') {
+    region->protection_flags |=
+        ProcessMemoryMaps::VMRegion::kProtectionFlagsWrite;
+  }
+  if (protection_flags[2] == 'x') {
+    region->protection_flags |=
+        ProcessMemoryMaps::VMRegion::kProtectionFlagsExec;
+  }
+
+  region->mapped_file = mapped_file;
+  TrimWhitespaceASCII(region->mapped_file, TRIM_ALL, &region->mapped_file);
+
+  return res;
+}
+
+uint64_t ReadCounterBytes(char* counter_line) {
+  uint64_t counter_value = 0;
+  int res = sscanf(counter_line, "%*s %" SCNu64 " kB", &counter_value);
+  DCHECK_EQ(1, res);
+  return counter_value * 1024;
+}
+
+uint32_t ParseSmapsCounter(char* counter_line,
+                           ProcessMemoryMaps::VMRegion* region) {
+  // A smaps counter lines looks as follows: "RSS:  0 Kb\n"
+  uint32_t res = 1;
+  char counter_name[20];
+  int did_read = sscanf(counter_line, "%19[^\n ]", counter_name);
+  DCHECK_EQ(1, did_read);
+
+  if (strcmp(counter_name, "Pss:") == 0) {
+    region->byte_stats_proportional_resident = ReadCounterBytes(counter_line);
+  } else if (strcmp(counter_name, "Private_Dirty:") == 0) {
+    region->byte_stats_private_dirty_resident = ReadCounterBytes(counter_line);
+  } else if (strcmp(counter_name, "Private_Clean:") == 0) {
+    region->byte_stats_private_clean_resident = ReadCounterBytes(counter_line);
+  } else if (strcmp(counter_name, "Shared_Dirty:") == 0) {
+    region->byte_stats_shared_dirty_resident = ReadCounterBytes(counter_line);
+  } else if (strcmp(counter_name, "Shared_Clean:") == 0) {
+    region->byte_stats_shared_clean_resident = ReadCounterBytes(counter_line);
+  } else if (strcmp(counter_name, "Swap:") == 0) {
+    region->byte_stats_swapped = ReadCounterBytes(counter_line);
+  } else {
+    res = 0;
+  }
+
+  return res;
+}
+
+uint32_t ReadLinuxProcSmapsFile(FILE* smaps_file, ProcessMemoryMaps* pmm) {
+  if (!smaps_file)
+    return 0;
+
+  fseek(smaps_file, 0, SEEK_SET);
+
+  char line[kMaxLineSize];
+  const uint32_t kNumExpectedCountersPerRegion = 6;
+  uint32_t counters_parsed_for_current_region = 0;
+  uint32_t num_valid_regions = 0;
+  ProcessMemoryMaps::VMRegion region;
+  bool should_add_current_region = false;
+  for (;;) {
+    line[0] = '\0';
+    if (fgets(line, kMaxLineSize, smaps_file) == nullptr)
+      break;
+    DCHECK_GT(strlen(line), 0u);
+    if (isxdigit(line[0]) && !isupper(line[0])) {
+      region = ProcessMemoryMaps::VMRegion();
+      counters_parsed_for_current_region = 0;
+      should_add_current_region = ParseSmapsHeader(line, &region);
+    } else {
+      counters_parsed_for_current_region += ParseSmapsCounter(line, &region);
+      DCHECK_LE(counters_parsed_for_current_region,
+                kNumExpectedCountersPerRegion);
+      if (counters_parsed_for_current_region == kNumExpectedCountersPerRegion) {
+        if (should_add_current_region) {
+          pmm->AddVMRegion(region);
+          ++num_valid_regions;
+          should_add_current_region = false;
+        }
+      }
+    }
+  }
+  return num_valid_regions;
+}
+
+}  // namespace
+
+// static
+ProcessMemoryMapsDumpProvider* ProcessMemoryMapsDumpProvider::GetInstance() {
+  return Singleton<ProcessMemoryMapsDumpProvider,
+                   LeakySingletonTraits<ProcessMemoryMapsDumpProvider>>::get();
+}
+
+ProcessMemoryMapsDumpProvider::ProcessMemoryMapsDumpProvider() {
+}
+
+ProcessMemoryMapsDumpProvider::~ProcessMemoryMapsDumpProvider() {
+}
+
+// Called at trace dump point time. Creates a snapshot of the memory maps for
+// the current process.
+bool ProcessMemoryMapsDumpProvider::OnMemoryDump(const MemoryDumpArgs& args,
+                                                 ProcessMemoryDump* pmd) {
+  // Snapshot of memory maps is not taken for light dump requests.
+  if (args.level_of_detail == MemoryDumpLevelOfDetail::LIGHT)
+    return true;
+
+  uint32_t res = 0;
+  if (UNLIKELY(proc_smaps_for_testing)) {
+    res = ReadLinuxProcSmapsFile(proc_smaps_for_testing, pmd->process_mmaps());
+  } else {
+    ScopedFILE smaps_file(fopen("/proc/self/smaps", "r"));
+    res = ReadLinuxProcSmapsFile(smaps_file.get(), pmd->process_mmaps());
+  }
+
+  if (res > 0) {
+    pmd->set_has_process_mmaps();
+    return true;
+  }
+  return false;
+}
+
+}  // namespace trace_event
+}  // namespace base