Revert of [tracing] Dump child processes' memory metrics in browser (patchset #1 id:1 of https://codereview.chromium.org/1591553002/ )

Reason for revert:
TracingBrowserTest.TestMemoryInfra is failing on DrMemory bot with the following
error:

UNADDRESSABLE ACCESS: reading 0x00000048-0x0000004c 4 byte(s)
# 0 base.dll!base::Thread::task_runner
[base\threading\thread.h:168]
# 1 base.dll!base::trace_event::MemoryDumpManager::CreateProcessDump
[base\trace_event\memory_dump_manager.cc:313]
# 2 content.dll!content::TracingControllerImpl::RequestGlobalMemoryDump
[content\browser\tracing\tracing_controller_impl.cc:1039]
# 3 content.dll!base::internal::Invoker<>::Run
[base\bind_internal.h:350]

bug: crbug.com/580295

Original issue's description:
> Reland of [tracing] Dump child processes' memory metrics in browser (patchset #1 id:1 of https://codereview.chromium.org/1586893003/ )
>
> The failure was due to flakiness fixed by crrev.com/1606983002.
> See crbug.com/578128.
>
> Original issue's description:
> > Revert of [tracing] Dump child processes' memory metrics in browser (patchset #15 id:400001 of https://codereview.chromium.org/1417003003/ )
> >
> > Reason for revert:
> > This is suspected by Findit to cause failure in TracingBrowserTest.TestMemoryInfra under Mac ASan 64 Tests (1).
> >
> > Original issue's description:
> > > [tracing] Dump child processes' memory metrics in browser
> > >
> > > The sandbox in linux prevents the process from reading the process
> > > metrics file. To work around this issue, the browser process will now
> > > dump statistics of the child processes too. This requires the
> > > composable dumps support in trace viewer and telemetry.
> > >
> > > This CL makes following changes.
> > > 1. Move the process totals and memory maps dump provider into a single
> > > header as process_metrics_dump_provider in components/tracing. This is
> > > because it is not necessary to have this in base and now the provider
> > > knows/manages for different processes. Also the dump method are made to
> > > handle error better, since process can vanish while dumping.
> > >
> > > 2. Make the dump provider non-singleton and have a register / unregister
> > > that manages the lifetime of the dump providers.
> > >
> > > 3. The dump providers unregister using the new
> > > UnregisterAndDeleteDumpProviderAsync api added by crrev.com/1430073002.
> > >
> > > 4. On linux the browser process dumps metrics for all processes and on
> > > android the child processes can dump since seccomp sandbox is not
> > > enabled in android yet.
> > >
> > > 5. The proc/status file is human readable stats and is not guaranteed to
> > > have a field that is asked for. So, the NOTREACHED is removed in
> > > ReadProcStatusAndGetFieldAsSizeT.
> > >
> > > 6. Since we introduce other process dumps from browser process there
> > > could be races while unregistering and dumping. To test this, the
> > > browser test is updated.
> > >
> > > BUG=461788
> > >
> > > Committed: https://crrev.com/4d77d76a42425282b1a3c5b7309db9b98e777f60
> > > Cr-Commit-Position: refs/heads/master@{#369482}
> >
> > TBR=primiano@chromium.org,thakis@chromium.org,simonhatch@chromium.org,sievers@chromium.org,ssid@chromium.org
> > # Skipping CQ checks because original CL landed less than 1 days ago.
> > NOPRESUBMIT=true
> > NOTREECHECKS=true
> > NOTRY=true
> > BUG=461788
> >
> > Committed: https://crrev.com/93aa967cfcb3e933000f169b9a4f7ac84dbd96da
> > Cr-Commit-Position: refs/heads/master@{#369535}
>
> TBR=primiano@chromium.org,thakis@chromium.org,simonhatch@chromium.org,sievers@chromium.org,huangs@chromium.org
> BUG=461788
> CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel
>
> Committed: https://crrev.com/df4156349708e21844209290a2d3638b550e18b2
> Cr-Commit-Position: refs/heads/master@{#370195}

TBR=primiano@chromium.org,thakis@chromium.org,simonhatch@chromium.org,sievers@chromium.org,huangs@chromium.org,ssid@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=461788

Review URL: https://codereview.chromium.org/1617263002

Cr-Commit-Position: refs/heads/master@{#370836}

10 files changed, 639 insertions, 2 deletions

diff --git a/base/BUILD.gn b/base/BUILD.gn
index 3f8380c..5e94b37 100644
--- a/base/BUILD.gn
+++ b/base/BUILD.gn
@@ -849,8 +849,11 @@ component("base") {
     "trace_event/process_memory_dump.h",
     "trace_event/process_memory_maps.cc",
     "trace_event/process_memory_maps.h",
+    "trace_event/process_memory_maps_dump_provider.h",
     "trace_event/process_memory_totals.cc",
     "trace_event/process_memory_totals.h",
+    "trace_event/process_memory_totals_dump_provider.cc",
+    "trace_event/process_memory_totals_dump_provider.h",
     "trace_event/trace_buffer.cc",
     "trace_event/trace_buffer.h",
     "trace_event/trace_config.cc",
@@ -991,6 +994,7 @@ component("base") {
       "sys_info_linux.cc",
       "trace_event/malloc_dump_provider.cc",
       "trace_event/malloc_dump_provider.h",
+      "trace_event/process_memory_maps_dump_provider.cc",
     ]
     set_sources_assignment_filter(sources_assignment_filter)
 
@@ -1057,6 +1061,7 @@ component("base") {
       "sync_socket_posix.cc",
       "sys_info.cc",
       "sys_info_posix.cc",
+      "trace_event/process_memory_totals_dump_provider.cc",
       "trace_event/trace_event_system_stats_monitor.cc",
     ]
 
@@ -1185,6 +1190,7 @@ component("base") {
     sources += [
       "trace_event/malloc_dump_provider.cc",
       "trace_event/malloc_dump_provider.h",
+      "trace_event/process_memory_maps_dump_provider.cc",
     ]
 
     if (is_asan || is_lsan || is_msan || is_tsan) {
@@ -1822,6 +1828,7 @@ test("base_unittests") {
     "trace_event/memory_allocator_dump_unittest.cc",
     "trace_event/memory_dump_manager_unittest.cc",
     "trace_event/process_memory_dump_unittest.cc",
+    "trace_event/process_memory_totals_dump_provider_unittest.cc",
     "trace_event/trace_config_memory_test_util.h",
     "trace_event/trace_config_unittest.cc",
     "trace_event/trace_event_argument_unittest.cc",
@@ -1938,6 +1945,10 @@ test("base_unittests") {
     }
   }
 
+  if (is_linux || is_android) {
+    sources += [ "trace_event/process_memory_maps_dump_provider_unittest.cc" ]
+  }
+
   if (!is_linux || use_ozone) {
     sources -= [ "message_loop/message_pump_glib_unittest.cc" ]
   }
diff --git a/base/process/process_metrics_linux.cc b/base/process/process_metrics_linux.cc
index 7a731bb..bcebcf5 100644
--- a/base/process/process_metrics_linux.cc
+++ b/base/process/process_metrics_linux.cc
@@ -86,8 +86,7 @@ size_t ReadProcStatusAndGetFieldAsSizeT(pid_t pid, const std::string& field) {
       return value;
     }
   }
-  // This can be reached if the process dies when proc is read -- in that case,
-  // the kernel can return missing fields.
+  NOTREACHED();
   return 0;
 }
 
diff --git a/base/trace_event/memory_dump_manager.cc b/base/trace_event/memory_dump_manager.cc
index eb82ac2..1f311b2 100644
--- a/base/trace_event/memory_dump_manager.cc
+++ b/base/trace_event/memory_dump_manager.cc
@@ -23,6 +23,14 @@
 #include "base/trace_event/trace_event_argument.h"
 #include "build/build_config.h"
 
+#if !defined(OS_NACL)
+#include "base/trace_event/process_memory_totals_dump_provider.h"
+#endif
+
+#if defined(OS_LINUX) || defined(OS_ANDROID)
+#include "base/trace_event/process_memory_maps_dump_provider.h"
+#endif
+
 #if defined(OS_ANDROID)
 #include "base/trace_event/java_heap_dump_provider_android.h"
 #endif
@@ -145,10 +153,20 @@ void MemoryDumpManager::Initialize(MemoryDumpManagerDelegate* delegate,
   }
 
 // Enable the core dump providers.
+#if !defined(OS_NACL)
+  RegisterDumpProvider(ProcessMemoryTotalsDumpProvider::GetInstance(),
+                       "ProcessMemoryTotals", nullptr);
+#endif
+
 #if defined(MALLOC_MEMORY_TRACING_SUPPORTED)
   RegisterDumpProvider(MallocDumpProvider::GetInstance(), "Malloc", nullptr);
 #endif
 
+#if defined(OS_LINUX) || defined(OS_ANDROID)
+  RegisterDumpProvider(ProcessMemoryMapsDumpProvider::GetInstance(),
+                       "ProcessMemoryMaps", nullptr);
+#endif
+
 #if defined(OS_ANDROID)
   RegisterDumpProvider(JavaHeapDumpProvider::GetInstance(), "JavaHeap",
                        nullptr);
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 0000000..4c3959f
--- /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
diff --git a/base/trace_event/process_memory_maps_dump_provider.h b/base/trace_event/process_memory_maps_dump_provider.h
new file mode 100644
index 0000000..84badfe
--- /dev/null
+++ b/base/trace_event/process_memory_maps_dump_provider.h
@@ -0,0 +1,43 @@
+// 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.
+
+#ifndef BASE_TRACE_EVENT_PROCESS_MEMORY_MAPS_DUMP_PROVIDER_H_
+#define BASE_TRACE_EVENT_PROCESS_MEMORY_MAPS_DUMP_PROVIDER_H_
+
+#include "base/gtest_prod_util.h"
+#include "base/macros.h"
+#include "base/memory/singleton.h"
+#include "base/trace_event/memory_dump_provider.h"
+#include "build/build_config.h"
+
+namespace base {
+namespace trace_event {
+
+// Dump provider which collects process-wide memory stats.
+class BASE_EXPORT ProcessMemoryMapsDumpProvider : public MemoryDumpProvider {
+ public:
+  static ProcessMemoryMapsDumpProvider* GetInstance();
+
+  // MemoryDumpProvider implementation.
+  bool OnMemoryDump(const MemoryDumpArgs& args,
+                    ProcessMemoryDump* pmd) override;
+
+ private:
+  friend struct DefaultSingletonTraits<ProcessMemoryMapsDumpProvider>;
+  FRIEND_TEST_ALL_PREFIXES(ProcessMemoryMapsDumpProviderTest, ParseProcSmaps);
+
+#if defined(OS_LINUX) || defined(OS_ANDROID) || defined(OS_NACL)
+  static FILE* proc_smaps_for_testing;
+#endif
+
+  ProcessMemoryMapsDumpProvider();
+  ~ProcessMemoryMapsDumpProvider() override;
+
+  DISALLOW_COPY_AND_ASSIGN(ProcessMemoryMapsDumpProvider);
+};
+
+}  // namespace trace_event
+}  // namespace base
+
+#endif  // BASE_TRACE_EVENT_PROCESS_MEMORY_MAPS_DUMP_PROVIDER_H_
diff --git a/base/trace_event/process_memory_maps_dump_provider_unittest.cc b/base/trace_event/process_memory_maps_dump_provider_unittest.cc
new file mode 100644
index 0000000..624f96f
--- /dev/null
+++ b/base/trace_event/process_memory_maps_dump_provider_unittest.cc
@@ -0,0 +1,190 @@
+// 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/file_util.h"
+#include "base/trace_event/process_memory_dump.h"
+#include "base/trace_event/process_memory_maps.h"
+#include "base/trace_event/trace_event_argument.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace base {
+namespace trace_event {
+
+namespace {
+const char kTestSmaps1[] =
+    "00400000-004be000 r-xp 00000000 fc:01 1234              /file/1\n"
+    "Size:                760 kB\n"
+    "Rss:                 296 kB\n"
+    "Pss:                 162 kB\n"
+    "Shared_Clean:        228 kB\n"
+    "Shared_Dirty:          0 kB\n"
+    "Private_Clean:         0 kB\n"
+    "Private_Dirty:        68 kB\n"
+    "Referenced:          296 kB\n"
+    "Anonymous:            68 kB\n"
+    "AnonHugePages:         0 kB\n"
+    "Swap:                  4 kB\n"
+    "KernelPageSize:        4 kB\n"
+    "MMUPageSize:           4 kB\n"
+    "Locked:                0 kB\n"
+    "VmFlags: rd ex mr mw me dw sd\n"
+    "ff000000-ff800000 -w-p 00001080 fc:01 0            /file/name with space\n"
+    "Size:                  0 kB\n"
+    "Rss:                 192 kB\n"
+    "Pss:                 128 kB\n"
+    "Shared_Clean:        120 kB\n"
+    "Shared_Dirty:          4 kB\n"
+    "Private_Clean:        60 kB\n"
+    "Private_Dirty:         8 kB\n"
+    "Referenced:          296 kB\n"
+    "Anonymous:             0 kB\n"
+    "AnonHugePages:         0 kB\n"
+    "Swap:                  0 kB\n"
+    "KernelPageSize:        4 kB\n"
+    "MMUPageSize:           4 kB\n"
+    "Locked:                0 kB\n"
+    "VmFlags: rd ex mr mw me dw sd";
+
+const char kTestSmaps2[] =
+    // An invalid region, with zero size and overlapping with the last one
+    // (See crbug.com/461237).
+    "7fe7ce79c000-7fe7ce79c000 ---p 00000000 00:00 0 \n"
+    "Size:                  4 kB\n"
+    "Rss:                   0 kB\n"
+    "Pss:                   0 kB\n"
+    "Shared_Clean:          0 kB\n"
+    "Shared_Dirty:          0 kB\n"
+    "Private_Clean:         0 kB\n"
+    "Private_Dirty:         0 kB\n"
+    "Referenced:            0 kB\n"
+    "Anonymous:             0 kB\n"
+    "AnonHugePages:         0 kB\n"
+    "Swap:                  0 kB\n"
+    "KernelPageSize:        4 kB\n"
+    "MMUPageSize:           4 kB\n"
+    "Locked:                0 kB\n"
+    "VmFlags: rd ex mr mw me dw sd\n"
+    // A invalid region with its range going backwards.
+    "00400000-00200000 ---p 00000000 00:00 0 \n"
+    "Size:                  4 kB\n"
+    "Rss:                   0 kB\n"
+    "Pss:                   0 kB\n"
+    "Shared_Clean:          0 kB\n"
+    "Shared_Dirty:          0 kB\n"
+    "Private_Clean:         0 kB\n"
+    "Private_Dirty:         0 kB\n"
+    "Referenced:            0 kB\n"
+    "Anonymous:             0 kB\n"
+    "AnonHugePages:         0 kB\n"
+    "Swap:                  0 kB\n"
+    "KernelPageSize:        4 kB\n"
+    "MMUPageSize:           4 kB\n"
+    "Locked:                0 kB\n"
+    "VmFlags: rd ex mr mw me dw sd\n"
+    // A good anonymous region at the end.
+    "7fe7ce79c000-7fe7ce7a8000 ---p 00000000 00:00 0 \n"
+    "Size:                 48 kB\n"
+    "Rss:                  40 kB\n"
+    "Pss:                  32 kB\n"
+    "Shared_Clean:         16 kB\n"
+    "Shared_Dirty:         12 kB\n"
+    "Private_Clean:         8 kB\n"
+    "Private_Dirty:         4 kB\n"
+    "Referenced:           40 kB\n"
+    "Anonymous:            16 kB\n"
+    "AnonHugePages:         0 kB\n"
+    "Swap:                  0 kB\n"
+    "KernelPageSize:        4 kB\n"
+    "MMUPageSize:           4 kB\n"
+    "Locked:                0 kB\n"
+    "VmFlags: rd wr mr mw me ac sd\n";
+
+void CreateAndSetSmapsFileForTesting(const char* smaps_string,
+                                     ScopedFILE& file) {
+  FilePath temp_path;
+  FILE* temp_file = CreateAndOpenTemporaryFile(&temp_path);
+  file.reset(temp_file);
+  ASSERT_TRUE(temp_file);
+
+  ASSERT_TRUE(base::WriteFileDescriptor(fileno(temp_file), smaps_string,
+                                        strlen(smaps_string)));
+}
+
+}  // namespace
+
+TEST(ProcessMemoryMapsDumpProviderTest, ParseProcSmaps) {
+  const uint32_t kProtR = ProcessMemoryMaps::VMRegion::kProtectionFlagsRead;
+  const uint32_t kProtW = ProcessMemoryMaps::VMRegion::kProtectionFlagsWrite;
+  const uint32_t kProtX = ProcessMemoryMaps::VMRegion::kProtectionFlagsExec;
+  const MemoryDumpArgs dump_args = {MemoryDumpLevelOfDetail::DETAILED};
+
+  auto pmmdp = ProcessMemoryMapsDumpProvider::GetInstance();
+
+  // Emulate an empty /proc/self/smaps.
+  ProcessMemoryDump pmd_invalid(nullptr /* session_state */);
+  ScopedFILE empty_file(OpenFile(FilePath("/dev/null"), "r"));
+  ASSERT_TRUE(empty_file.get());
+  ProcessMemoryMapsDumpProvider::proc_smaps_for_testing = empty_file.get();
+  pmmdp->OnMemoryDump(dump_args, &pmd_invalid);
+  ASSERT_FALSE(pmd_invalid.has_process_mmaps());
+
+  // Parse the 1st smaps file.
+  ProcessMemoryDump pmd_1(nullptr /* session_state */);
+  ScopedFILE temp_file1;
+  CreateAndSetSmapsFileForTesting(kTestSmaps1, temp_file1);
+  ProcessMemoryMapsDumpProvider::proc_smaps_for_testing = temp_file1.get();
+  pmmdp->OnMemoryDump(dump_args, &pmd_1);
+  ASSERT_TRUE(pmd_1.has_process_mmaps());
+  const auto& regions_1 = pmd_1.process_mmaps()->vm_regions();
+  ASSERT_EQ(2UL, regions_1.size());
+
+  EXPECT_EQ(0x00400000UL, regions_1[0].start_address);
+  EXPECT_EQ(0x004be000UL - 0x00400000UL, regions_1[0].size_in_bytes);
+  EXPECT_EQ(kProtR | kProtX, regions_1[0].protection_flags);
+  EXPECT_EQ("/file/1", regions_1[0].mapped_file);
+  EXPECT_EQ(162 * 1024UL, regions_1[0].byte_stats_proportional_resident);
+  EXPECT_EQ(228 * 1024UL, regions_1[0].byte_stats_shared_clean_resident);
+  EXPECT_EQ(0UL, regions_1[0].byte_stats_shared_dirty_resident);
+  EXPECT_EQ(0UL, regions_1[0].byte_stats_private_clean_resident);
+  EXPECT_EQ(68 * 1024UL, regions_1[0].byte_stats_private_dirty_resident);
+  EXPECT_EQ(4 * 1024UL, regions_1[0].byte_stats_swapped);
+
+  EXPECT_EQ(0xff000000UL, regions_1[1].start_address);
+  EXPECT_EQ(0xff800000UL - 0xff000000UL, regions_1[1].size_in_bytes);
+  EXPECT_EQ(kProtW, regions_1[1].protection_flags);
+  EXPECT_EQ("/file/name with space", regions_1[1].mapped_file);
+  EXPECT_EQ(128 * 1024UL, regions_1[1].byte_stats_proportional_resident);
+  EXPECT_EQ(120 * 1024UL, regions_1[1].byte_stats_shared_clean_resident);
+  EXPECT_EQ(4 * 1024UL, regions_1[1].byte_stats_shared_dirty_resident);
+  EXPECT_EQ(60 * 1024UL, regions_1[1].byte_stats_private_clean_resident);
+  EXPECT_EQ(8 * 1024UL, regions_1[1].byte_stats_private_dirty_resident);
+  EXPECT_EQ(0 * 1024UL, regions_1[1].byte_stats_swapped);
+
+  // Parse the 2nd smaps file.
+  ProcessMemoryDump pmd_2(nullptr /* session_state */);
+  ScopedFILE temp_file2;
+  CreateAndSetSmapsFileForTesting(kTestSmaps2, temp_file2);
+  ProcessMemoryMapsDumpProvider::proc_smaps_for_testing = temp_file2.get();
+  pmmdp->OnMemoryDump(dump_args, &pmd_2);
+  ASSERT_TRUE(pmd_2.has_process_mmaps());
+  const auto& regions_2 = pmd_2.process_mmaps()->vm_regions();
+  ASSERT_EQ(1UL, regions_2.size());
+  EXPECT_EQ(0x7fe7ce79c000UL, regions_2[0].start_address);
+  EXPECT_EQ(0x7fe7ce7a8000UL - 0x7fe7ce79c000UL, regions_2[0].size_in_bytes);
+  EXPECT_EQ(0U, regions_2[0].protection_flags);
+  EXPECT_EQ("", regions_2[0].mapped_file);
+  EXPECT_EQ(32 * 1024UL, regions_2[0].byte_stats_proportional_resident);
+  EXPECT_EQ(16 * 1024UL, regions_2[0].byte_stats_shared_clean_resident);
+  EXPECT_EQ(12 * 1024UL, regions_2[0].byte_stats_shared_dirty_resident);
+  EXPECT_EQ(8 * 1024UL, regions_2[0].byte_stats_private_clean_resident);
+  EXPECT_EQ(4 * 1024UL, regions_2[0].byte_stats_private_dirty_resident);
+  EXPECT_EQ(0 * 1024UL, regions_2[0].byte_stats_swapped);
+}
+
+}  // namespace trace_event
+}  // namespace base
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 0000000..1713ebf
--- /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
diff --git a/base/trace_event/process_memory_totals_dump_provider.h b/base/trace_event/process_memory_totals_dump_provider.h
new file mode 100644
index 0000000..d9573d3
--- /dev/null
+++ b/base/trace_event/process_memory_totals_dump_provider.h
@@ -0,0 +1,48 @@
+// 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.
+
+#ifndef BASE_TRACE_EVENT_PROCESS_MEMORY_TOTALS_DUMP_PROVIDER_H_
+#define BASE_TRACE_EVENT_PROCESS_MEMORY_TOTALS_DUMP_PROVIDER_H_
+
+#include <stdint.h>
+
+#include "base/gtest_prod_util.h"
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/singleton.h"
+#include "base/trace_event/memory_dump_provider.h"
+
+namespace base {
+
+class ProcessMetrics;
+
+namespace trace_event {
+
+// Dump provider which collects process-wide memory stats.
+class BASE_EXPORT ProcessMemoryTotalsDumpProvider : public MemoryDumpProvider {
+ public:
+  static ProcessMemoryTotalsDumpProvider* GetInstance();
+
+  // MemoryDumpProvider implementation.
+  bool OnMemoryDump(const MemoryDumpArgs& args,
+                    ProcessMemoryDump* pmd) override;
+
+ private:
+  friend struct DefaultSingletonTraits<ProcessMemoryTotalsDumpProvider>;
+  FRIEND_TEST_ALL_PREFIXES(ProcessMemoryTotalsDumpProviderTest, DumpRSS);
+
+  static uint64_t rss_bytes_for_testing;
+
+  ProcessMemoryTotalsDumpProvider();
+  ~ProcessMemoryTotalsDumpProvider() override;
+
+  scoped_ptr<ProcessMetrics> process_metrics_;
+
+  DISALLOW_COPY_AND_ASSIGN(ProcessMemoryTotalsDumpProvider);
+};
+
+}  // namespace trace_event
+}  // namespace base
+
+#endif  // BASE_TRACE_EVENT_PROCESS_MEMORY_TOTALS_DUMP_PROVIDER_H_
diff --git a/base/trace_event/process_memory_totals_dump_provider_unittest.cc b/base/trace_event/process_memory_totals_dump_provider_unittest.cc
new file mode 100644
index 0000000..d3f517e
--- /dev/null
+++ b/base/trace_event/process_memory_totals_dump_provider_unittest.cc
@@ -0,0 +1,48 @@
+// 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 <stdint.h>
+
+#include "base/trace_event/process_memory_dump.h"
+#include "base/trace_event/process_memory_totals.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace base {
+namespace trace_event {
+
+TEST(ProcessMemoryTotalsDumpProviderTest, DumpRSS) {
+  const MemoryDumpArgs high_detail_args = {MemoryDumpLevelOfDetail::DETAILED};
+  auto pmtdp = ProcessMemoryTotalsDumpProvider::GetInstance();
+  scoped_ptr<ProcessMemoryDump> pmd_before(new ProcessMemoryDump(nullptr));
+  scoped_ptr<ProcessMemoryDump> pmd_after(new ProcessMemoryDump(nullptr));
+
+  ProcessMemoryTotalsDumpProvider::rss_bytes_for_testing = 1024;
+  pmtdp->OnMemoryDump(high_detail_args, pmd_before.get());
+
+  // Pretend that the RSS of the process increased of +1M.
+  const size_t kAllocSize = 1048576;
+  ProcessMemoryTotalsDumpProvider::rss_bytes_for_testing += kAllocSize;
+
+  pmtdp->OnMemoryDump(high_detail_args, pmd_after.get());
+
+  ProcessMemoryTotalsDumpProvider::rss_bytes_for_testing = 0;
+
+  ASSERT_TRUE(pmd_before->has_process_totals());
+  ASSERT_TRUE(pmd_after->has_process_totals());
+
+  const uint64_t rss_before =
+      pmd_before->process_totals()->resident_set_bytes();
+  const uint64_t rss_after = pmd_after->process_totals()->resident_set_bytes();
+
+  EXPECT_NE(0U, rss_before);
+  EXPECT_NE(0U, rss_after);
+
+  EXPECT_EQ(rss_after - rss_before, kAllocSize);
+}
+
+}  // namespace trace_event
+}  // namespace base
diff --git a/base/trace_event/trace_event.gypi b/base/trace_event/trace_event.gypi
index 090f7da..6948d7c 100644
--- a/base/trace_event/trace_event.gypi
+++ b/base/trace_event/trace_event.gypi
@@ -36,8 +36,11 @@
       'trace_event/process_memory_dump.h',
       'trace_event/process_memory_maps.cc',
       'trace_event/process_memory_maps.h',
+      'trace_event/process_memory_maps_dump_provider.h',
       'trace_event/process_memory_totals.cc',
       'trace_event/process_memory_totals.h',
+      'trace_event/process_memory_totals_dump_provider.cc',
+      'trace_event/process_memory_totals_dump_provider.h',
       'trace_event/trace_buffer.cc',
       'trace_event/trace_buffer.h',
       'trace_event/trace_config.cc',
@@ -76,6 +79,7 @@
       'trace_event/memory_allocator_dump_unittest.cc',
       'trace_event/memory_dump_manager_unittest.cc',
       'trace_event/process_memory_dump_unittest.cc',
+      'trace_event/process_memory_totals_dump_provider_unittest.cc',
       'trace_event/trace_config_memory_test_util.h',
       'trace_event/trace_config_unittest.cc',
       'trace_event/trace_event_argument_unittest.cc',
@@ -91,6 +95,14 @@
           'trace_event/malloc_dump_provider.h',
         ],
       }],
+      ['OS == "linux" or OS == "android"', {
+          'trace_event_sources': [
+            'trace_event/process_memory_maps_dump_provider.cc',
+          ],
+          'trace_event_test_sources' : [
+            'trace_event/process_memory_maps_dump_provider_unittest.cc',
+          ],
+      }],
       ['OS == "android"', {
         'trace_event_test_sources' : [
           'trace_event/trace_event_android_unittest.cc',