cros: Replace "TPM" with "secure module" for machines without TPM.

chromeos/tpm/tpm_token_info_getter.cc

Index: chromeos/tpm/tpm_token_info_getter.cc
diff --git a/chromeos/tpm/tpm_token_info_getter.cc b/chromeos/tpm/tpm_token_info_getter.cc
index 1e7918d03c016ab2b6bd074ab0bb3a8126a50cd6..ec52980a48b510893d50837db04ccb1aba4f2374 100644
--- a/chromeos/tpm/tpm_token_info_getter.cc
+++ b/chromeos/tpm/tpm_token_info_getter.cc
@@ -7,6 +7,8 @@
 #include <stdint.h>
 
 #include "base/bind.h"
+#include "base/files/file_path.h"
+#include "base/files/file_util.h"
 #include "base/location.h"
 #include "base/task_runner.h"
 #include "chromeos/cryptohome/cryptohome_parameters.h"
@@ -17,6 +19,11 @@ namespace {
 const int64_t kInitialRequestDelayMs = 100;
 const int64_t kMaxRequestDelayMs = 300000;  // 5 minutes
 
+// If either of these two files exist, then we are not using TPM.
+constexpr char kNoTPMIndicatorFile1[] =

[apronin, 2017/05/02 16:43:38]

I'd go with 'NoTPMIndicator' -> 'Cr50UsedIndicator'. Or, ->
'TPMNotUsedIndicator'

[sammiequon, 2017/05/02 17:27:23]

Done.

+    "/opt/google/cr50/firmware/cr50.bin.prod";
+constexpr char kNoTPMIndicatorFile2[] = "/etc/init/cr50-update.conf";
+
 // Calculates the delay before running next attempt to initiatialize the TPM
 // token, if |last_delay| was the last or initial delay.
 base::TimeDelta GetNextRequestDelayMs(base::TimeDelta last_delay) {
@@ -61,6 +68,11 @@ std::unique_ptr<TPMTokenInfoGetter> TPMTokenInfoGetter::CreateForSystemToken(
       TYPE_SYSTEM, EmptyAccountId(), cryptohome_client, delayed_task_runner));
 }
 
+bool TPMTokenInfoGetter::DoesTPMExist() {

[apronin, 2017/05/02 16:43:38]

Does what is supposed to do for the purposes of the patch. But I'd rename and
revert the logic just to minimize potential confusion in the future. In theory,
several chips, including a TPM and an H1 with Cr50 can exist on the same system.
It counts not what exists, but what is used. So, I'd do something like:

bool TPMTokenInfoGetter::IsCr50Used() {
   return base::PathExists(base::FilePath(kCr50UsedIndicatorFile1)) ||
          base::PathExists(base::FilePath(kCr50UsedIndicatorFile2));
}

Or, at least switch from 'DoesExist' to 'IsUsed', though that may confuse future
readers: are we talking about a security module (which, even in cr50 case, in
everyday life may be referred to as tpm for brevity) not being used and going
with software-based approach, or are we talking about using h1+cr50 instead of a
tpm:

bool TPMTokenInfoGetter::IsTPMUsed() {
   return !base::PathExists(base::FilePath(kCr50UsedIndicatorFile1)) &&
          !base::PathExists(base::FilePath(kCr50UsedIndicatorFile2));
}

[sammiequon, 2017/05/02 17:27:23]

Done.

+  return !base::PathExists(base::FilePath(kNoTPMIndicatorFile1)) &&
+         !base::PathExists(base::FilePath(kNoTPMIndicatorFile2));
+}
+
 TPMTokenInfoGetter::~TPMTokenInfoGetter() {}
 
 void TPMTokenInfoGetter::Start(const TPMTokenInfoCallback& callback) {