Implement SysInfo::HardwareModelName() on iOS.

base/sys_info_ios.mm

Index: base/sys_info_ios.mm
diff --git a/base/sys_info_ios.mm b/base/sys_info_ios.mm
index 9a329b9f0924bbdefce908cd51de4a6488c574f0..7dc4effed932680d9a271609192e7d87c10fcd04 100644
--- a/base/sys_info_ios.mm
+++ b/base/sys_info_ios.mm
@@ -101,4 +101,13 @@ std::string SysInfo::CPUModelName() {
   return std::string();
 }
 
+// static
+std::string SysInfo::HardwareModelName() {
+  char model[256];
+  size_t len = sizeof(model);
+  if (sysctlbyname("hw.model", model, &len, NULL, 0) == 0)
+    return std::string(model, 0, len);

[Mark Mentovai, 2017/05/04 16:29:13]

This is weird. I don’t think that there’s a std::string constructor that accepts
(const char*, size_t, size_t). This is probably converting the char* into a
std::string and using the (const std::string&, size_t, size_t) constructor.
Yech.

You know that you have a NUL-terminated string on your hands, so
  DCHECK_GE(len, 1);  // and if you really want to, DCHECK_EQ(model[len - 1],
'\0')
  return std::string(model, len - 1);

[Alexei Svitkine (slow), 2017/05/04 16:44:07]

Good catch - done for both Mac and iOS and made CPUModelName() use the same
logic as well.

+  return std::string();
+}
+
 }  // namespace base