Type conversion fixes, crypto/ edition.

This is mostly to fix MSVC warnings about possible value truncation.

BUG=81439
TEST=none

Review URL: https://codereview.chromium.org/659943004

Cr-Commit-Position: refs/heads/master@{#300432}

3 files changed, 27 insertions, 22 deletions

diff --git a/crypto/ec_private_key_nss.cc b/crypto/ec_private_key_nss.cc
index b38c396..2daa0c0 100644
--- a/crypto/ec_private_key_nss.cc
+++ b/crypto/ec_private_key_nss.cc
@@ -340,7 +340,7 @@ ECPrivateKey* ECPrivateKey::CreateWithParams(PK11SlotInfo* slot,
   };
 
   ec_parameters.data[0] = SEC_ASN1_OBJECT_ID;
-  ec_parameters.data[1] = oid_data->oid.len;
+  ec_parameters.data[1] = static_cast<unsigned char>(oid_data->oid.len);
   memcpy(ec_parameters.data + 2, oid_data->oid.data, oid_data->oid.len);
 
   result->key_ = PK11_GenerateKeyPair(slot,
diff --git a/crypto/nss_util_unittest.cc b/crypto/nss_util_unittest.cc
index b687885..2859191 100644
--- a/crypto/nss_util_unittest.cc
+++ b/crypto/nss_util_unittest.cc
@@ -19,14 +19,17 @@ TEST(NSSUtilTest, PRTimeConversion) {
   prxtime.tm_params.tp_gmt_offset = 0;
   prxtime.tm_params.tp_dst_offset = 0;
   base::Time::Exploded exploded;
-  prxtime.tm_year = exploded.year = 2011;
+  exploded.year = prxtime.tm_year = 2011;
   exploded.month = 12;
   prxtime.tm_month = 11;
-  prxtime.tm_wday = exploded.day_of_week = 0;  // Should be unusued.
-  prxtime.tm_mday = exploded.day_of_month = 10;
-  prxtime.tm_hour = exploded.hour = 2;
-  prxtime.tm_min = exploded.minute = 52;
-  prxtime.tm_sec = exploded.second = 19;
+  // PRExplodedTime::tm_wday is a smaller type than Exploded::day_of_week, so
+  // assigning the two in this order instead of the reverse avoids potential
+  // warnings about type downcasting.
+  exploded.day_of_week = prxtime.tm_wday = 0;  // Should be unused.
+  exploded.day_of_month = prxtime.tm_mday = 10;
+  exploded.hour = prxtime.tm_hour = 2;
+  exploded.minute = prxtime.tm_min = 52;
+  exploded.second = prxtime.tm_sec = 19;
   exploded.millisecond = 342;
   prxtime.tm_usec = 342000;
 
diff --git a/crypto/signature_verifier_unittest.cc b/crypto/signature_verifier_unittest.cc
index 3329799..f6c42e0 100644
--- a/crypto/signature_verifier_unittest.cc
+++ b/crypto/signature_verifier_unittest.cc
@@ -3,6 +3,8 @@
 // found in the LICENSE file.
 
 #include "crypto/signature_verifier.h"
+
+#include "base/numerics/safe_conversions.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 TEST(SignatureVerifierTest, BasicTest) {
@@ -1005,36 +1007,36 @@ static bool EncodeRSAPublicKey(const std::vector<uint8>& modulus_n,
   public_key_info->insert(public_key_info->begin(),
                           public_exponent_e.begin(),
                           public_exponent_e.end());
-  uint8 length = public_exponent_e.size();
-  public_key_info->insert(public_key_info->begin(), length);
+  uint8 exponent_size = base::checked_cast<uint8>(public_exponent_e.size());
+  public_key_info->insert(public_key_info->begin(), exponent_size);
   public_key_info->insert(public_key_info->begin(), kIntegerTag);
 
   // Encode the modulus n as an INTEGER.
   public_key_info->insert(public_key_info->begin(),
                           modulus_n.begin(), modulus_n.end());
-  uint16 length16 = modulus_n.size();
+  uint16 modulus_size = base::checked_cast<uint16>(modulus_n.size());
   if (modulus_n[0] & 0x80) {
     public_key_info->insert(public_key_info->begin(), 0x00);
-    length16++;
+    modulus_size++;
   }
-  public_key_info->insert(public_key_info->begin(), length16 & 0xff);
-  public_key_info->insert(public_key_info->begin(), (length16 >> 8) & 0xff);
+  public_key_info->insert(public_key_info->begin(), modulus_size & 0xff);
+  public_key_info->insert(public_key_info->begin(), (modulus_size >> 8) & 0xff);
   public_key_info->insert(public_key_info->begin(), 0x82);
   public_key_info->insert(public_key_info->begin(), kIntegerTag);
 
   // Encode the RSAPublicKey SEQUENCE.
-  length16 = public_key_info->size();
-  public_key_info->insert(public_key_info->begin(), length16 & 0xff);
-  public_key_info->insert(public_key_info->begin(), (length16 >> 8) & 0xff);
+  uint16 info_size = base::checked_cast<uint16>(public_key_info->size());
+  public_key_info->insert(public_key_info->begin(), info_size & 0xff);
+  public_key_info->insert(public_key_info->begin(), (info_size >> 8) & 0xff);
   public_key_info->insert(public_key_info->begin(), 0x82);
   public_key_info->insert(public_key_info->begin(), kSequenceTag);
 
   // Encode the BIT STRING.
   // Number of unused bits.
   public_key_info->insert(public_key_info->begin(), 0x00);
-  length16 = public_key_info->size();
-  public_key_info->insert(public_key_info->begin(), length16 & 0xff);
-  public_key_info->insert(public_key_info->begin(), (length16 >> 8) & 0xff);
+  info_size = base::checked_cast<uint16>(public_key_info->size());
+  public_key_info->insert(public_key_info->begin(), info_size & 0xff);
+  public_key_info->insert(public_key_info->begin(), (info_size >> 8) & 0xff);
   public_key_info->insert(public_key_info->begin(), 0x82);
   public_key_info->insert(public_key_info->begin(), kBitStringTag);
 
@@ -1049,9 +1051,9 @@ static bool EncodeRSAPublicKey(const std::vector<uint8>& modulus_n,
                           algorithm, algorithm + sizeof(algorithm));
 
   // Encode the outermost SEQUENCE.
-  length16 = public_key_info->size();
-  public_key_info->insert(public_key_info->begin(), length16 & 0xff);
-  public_key_info->insert(public_key_info->begin(), (length16 >> 8) & 0xff);
+  info_size = base::checked_cast<uint16>(public_key_info->size());
+  public_key_info->insert(public_key_info->begin(), info_size & 0xff);
+  public_key_info->insert(public_key_info->begin(), (info_size >> 8) & 0xff);
   public_key_info->insert(public_key_info->begin(), 0x82);
   public_key_info->insert(public_key_info->begin(), kSequenceTag);