[NOT TO COMMIT YET] Using proc/pid/status file contents to get process metrics in linux.

base/process/process_metrics_unittest.cc

Index: base/process/process_metrics_unittest.cc
diff --git a/base/process/process_metrics_unittest.cc b/base/process/process_metrics_unittest.cc
index 31479cefff64f5b0dc17c960b317bae45bec3b0e..4172402c3c51b733fa9cf37a89ccf14e79bd52fa 100644
--- a/base/process/process_metrics_unittest.cc
+++ b/base/process/process_metrics_unittest.cc
@@ -268,6 +268,57 @@ TEST_F(SystemMetricsTest, ParseVmstat) {
   EXPECT_EQ(meminfo.pswpout, 901);
   EXPECT_EQ(meminfo.pgmajfault, 2023);
 }
+
+TEST(ProcessMetricsTest, ParseProcStatusFile) {
+  std::string valid_status_contents =
+    "Name:   bash\n"
+    "State:  S (sleeping)\n"
+    "Tgid:   3515\n"
+    "Pid:    3515\n"
+    "PPid:   3452\n"
+    "TracerPid:      0\n"
+    "Uid:    1000    1000    1000    1000\n"
+    "Gid:    100     100     100     100\n"
+    "FDSize: 256\n"
+    "Groups: 16 33 100\n"
+    "VmPeak:     9136 kB\n"
+    "VmSize:     7896 kB\n"
+    "VmLck:         0 kB\n"
+    "VmPin:         0 kB\n"
+    "VmHWM:      7572 kB\n"
+    "VmRSS:      6316 kB\n"
+    "VmData:     5224 kB\n"
+    "VmStk:        88 kB\n"
+    "VmExe:       572 kB\n"
+    "VmLib:      1708 kB\n"
+    "VmPMD:         4 kB\n"
+    "VmPTE:        20 kB\n"
+    "VmSwap:        0 kB\n"
+    "Threads:        1\n"
+    "SigQ:   0/3067\n"
+    "SigPnd: 0000000000000000\n"
+    "ShdPnd: 0000000000000000\n"
+    "SigBlk: 0000000000010000\n"
+    "SigIgn: 0000000000384004\n"
+    "SigCgt: 000000004b813efb\n"
+    "CapInh: 0000000000000000\n"
+    "CapPrm: 0000000000000000\n"
+    "CapEff: 0000000000000000\n"
+    "CapBnd: ffffffffffffffff\n"
+    "Seccomp:        0\n"
+    "Cpus_allowed:   00000001\n"
+    "Cpus_allowed_list:      0\n"
+    "Mems_allowed:   1\n"
+    "Mems_allowed_list:      0\n"
+    "voluntary_ctxt_switches:        150\n"
+    "nonvoluntary_ctxt_switches:     545\n";
+
+  size_t vm_size;
+  bool res =
+      ParseProcStatusAndGetField(valid_status_contents, "VmSize", &vm_size);
+  EXPECT_TRUE(res);
+  EXPECT_EQ(vm_size, 7896 * 1024u);
+}
 #endif  // defined(OS_LINUX) || defined(OS_ANDROID)
 
 #if defined(OS_WIN) || (defined(OS_MACOSX) && !defined(OS_IOS)) || \