Split ProcessHandle and its related routines into base/process/process_handle.h.

base/process/process_metrics_ios.cc

Index: base/process/process_metrics_ios.cc
diff --git a/base/process/process_metrics_ios.cc b/base/process/process_metrics_ios.cc
index 9f0e8c6ba98603db8a4da4dda3d6ea9c2af59bbd..94c671901b6ee97affcca3c21695abff4d935e2a 100644
--- a/base/process/process_metrics_ios.cc
+++ b/base/process/process_metrics_ios.cc
@@ -44,4 +44,21 @@ size_t ProcessMetrics::GetWorkingSetSize() const {
   return task_info_data.resident_size;
 }
 
+size_t GetMaxFds() {
+  static const rlim_t kSystemDefaultMaxFds = 256;
+  rlim_t max_fds;
+  struct rlimit nofile;
+  if (getrlimit(RLIMIT_NOFILE, &nofile)) {
+    // Error case: Take a best guess.
+    max_fds = kSystemDefaultMaxFds;
+  } else {
+    max_fds = nofile.rlim_cur;
+  }
+
+  if (max_fds > INT_MAX)
+    max_fds = INT_MAX;
+
+  return static_cast<size_t>(max_fds);
+}
+
 }  // namespace base