Revert of RTCCertificate::Expires() and ::HasExpired() implemented (patchset #5 id:140001 of https://codereview.webrtc.org/1494103003/ )

Reason for revert:
RTCCertificate's expires_timestamp_ns was renamed to Expires but the old function is still used in one place in Chromium...
https://uberchromegw.corp.google.com/i/chromium.webrtc.fyi/builders/Mac%20Builder/builds/7405

Original issue's description:
> RTCCertificate::Expires() and ::HasExpired() implemented using SSLCertificate::CertificateExpirationTime().
>
> NOPRESUBMIT=true
> BUG=chromium:544894
>
> Committed: https://crrev.com/20ef654174e245b3a06c9e9045bb97be9acd90cf
> Cr-Commit-Position: refs/heads/master@{#10930}

TBR=torbjorng@webrtc.org,hta@webrtc.org,kjellander@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:544894

Review URL: https://codereview.webrtc.org/1506883005

Cr-Commit-Position: refs/heads/master@{#10933}

6 files changed, 12 insertions, 144 deletions

diff --git a/webrtc/base/base_tests.gyp b/webrtc/base/base_tests.gyp
index 1da93defd4..23b1f9a15e 100644
--- a/webrtc/base/base_tests.gyp
+++ b/webrtc/base/base_tests.gyp
@@ -88,7 +88,6 @@
           'ratetracker_unittest.cc',
           'referencecountedsingletonfactory_unittest.cc',
           'rollingaccumulator_unittest.cc',
-          'rtccertificate_unittests.cc',
           'scopedptrcollection_unittest.cc',
           'sha1digest_unittest.cc',
           'sharedexclusivelock_unittest.cc',
diff --git a/webrtc/base/fakesslidentity.h b/webrtc/base/fakesslidentity.h
index ec603a541d..69d590b5eb 100644
--- a/webrtc/base/fakesslidentity.h
+++ b/webrtc/base/fakesslidentity.h
@@ -25,11 +25,9 @@ class FakeSSLCertificate : public rtc::SSLCertificate {
   // SHA-1 is the default digest algorithm because it is available in all build
   // configurations used for unit testing.
   explicit FakeSSLCertificate(const std::string& data)
-      : data_(data), digest_algorithm_(DIGEST_SHA_1), expiration_time_(-1) {}
+      : data_(data), digest_algorithm_(DIGEST_SHA_1) {}
   explicit FakeSSLCertificate(const std::vector<std::string>& certs)
-      : data_(certs.front()),
-        digest_algorithm_(DIGEST_SHA_1),
-        expiration_time_(-1) {
+      : data_(certs.front()), digest_algorithm_(DIGEST_SHA_1) {
     std::vector<std::string>::const_iterator it;
     // Skip certs[0].
     for (it = certs.begin() + 1; it != certs.end(); ++it) {
@@ -47,12 +45,7 @@ class FakeSSLCertificate : public rtc::SSLCertificate {
     VERIFY(SSLIdentity::PemToDer(kPemTypeCertificate, data_, &der_string));
     der_buffer->SetData(der_string.c_str(), der_string.size());
   }
-  int64_t CertificateExpirationTime() const override {
-    return expiration_time_;
-  }
-  void SetCertificateExpirationTime(int64_t expiration_time) {
-    expiration_time_ = expiration_time;
-  }
+  int64_t CertificateExpirationTime() const override { return -1; }
   void set_digest_algorithm(const std::string& algorithm) {
     digest_algorithm_ = algorithm;
   }
@@ -86,8 +79,6 @@ class FakeSSLCertificate : public rtc::SSLCertificate {
   std::string data_;
   std::vector<FakeSSLCertificate> certs_;
   std::string digest_algorithm_;
-  // Expiration time in seconds relative to epoch, 1970-01-01T00:00:00Z (UTC).
-  int64_t expiration_time_;
 };
 
 class FakeSSLIdentity : public rtc::SSLIdentity {
diff --git a/webrtc/base/rtccertificate.cc b/webrtc/base/rtccertificate.cc
index 7b764bd72e..a176d9080b 100644
--- a/webrtc/base/rtccertificate.cc
+++ b/webrtc/base/rtccertificate.cc
@@ -11,6 +11,7 @@
 #include "webrtc/base/rtccertificate.h"
 
 #include "webrtc/base/checks.h"
+#include "webrtc/base/timeutils.h"
 
 namespace rtc {
 
@@ -27,16 +28,13 @@ RTCCertificate::RTCCertificate(SSLIdentity* identity)
 RTCCertificate::~RTCCertificate() {
 }
 
-uint64_t RTCCertificate::Expires() const {
-  int64_t expires = ssl_certificate().CertificateExpirationTime();
-  if (expires != -1)
-    return static_cast<uint64_t>(expires) * kNumMillisecsPerSec;
-  // If the expiration time could not be retrieved return an expired timestamp.
-  return 0;  // = 1970-01-01
+uint64_t RTCCertificate::expires_timestamp_ns() const {
+  // TODO(hbos): Update once SSLIdentity/SSLCertificate supports expires field.
+  return 0;
 }
 
-bool RTCCertificate::HasExpired(uint64_t now) const {
-  return Expires() <= now;
+bool RTCCertificate::HasExpired() const {
+  return expires_timestamp_ns() <= TimeNanos();
 }
 
 const SSLCertificate& RTCCertificate::ssl_certificate() const {
diff --git a/webrtc/base/rtccertificate.h b/webrtc/base/rtccertificate.h
index 600739bc86..d238938ae1 100644
--- a/webrtc/base/rtccertificate.h
+++ b/webrtc/base/rtccertificate.h
@@ -27,11 +27,8 @@ class RTCCertificate : public RefCountInterface {
   // Takes ownership of |identity|.
   static scoped_refptr<RTCCertificate> Create(scoped_ptr<SSLIdentity> identity);
 
-  // Returns the expiration time in ms relative to epoch, 1970-01-01T00:00:00Z.
-  uint64_t Expires() const;
-  // Checks if the certificate has expired, where |now| is expressed in ms
-  // relative to epoch, 1970-01-01T00:00:00Z.
-  bool HasExpired(uint64_t now) const;
+  uint64_t expires_timestamp_ns() const;
+  bool HasExpired() const;
   const SSLCertificate& ssl_certificate() const;
 
   // TODO(hbos): If possible, remove once RTCCertificate and its
diff --git a/webrtc/base/rtccertificate_unittests.cc b/webrtc/base/rtccertificate_unittests.cc
deleted file mode 100644
index 3e9439fedb..0000000000
--- a/webrtc/base/rtccertificate_unittests.cc
+++ /dev/null
@@ -1,116 +0,0 @@
-/*
- *  Copyright 2015 The WebRTC Project Authors. All rights reserved.
- *
- *  Use of this source code is governed by a BSD-style license
- *  that can be found in the LICENSE file in the root of the source
- *  tree. An additional intellectual property rights grant can be found
- *  in the file PATENTS.  All contributing project authors may
- *  be found in the AUTHORS file in the root of the source tree.
- */
-
-#include "webrtc/base/checks.h"
-#include "webrtc/base/fakesslidentity.h"
-#include "webrtc/base/gunit.h"
-#include "webrtc/base/logging.h"
-#include "webrtc/base/rtccertificate.h"
-#include "webrtc/base/safe_conversions.h"
-#include "webrtc/base/scoped_ptr.h"
-#include "webrtc/base/sslidentity.h"
-#include "webrtc/base/thread.h"
-#include "webrtc/base/timeutils.h"
-
-namespace rtc {
-
-namespace {
-
-static const char* kTestCertCommonName = "RTCCertificateTest's certificate";
-
-}  // namespace
-
-class RTCCertificateTest : public testing::Test {
- public:
-  RTCCertificateTest() {}
-  ~RTCCertificateTest() {}
-
- protected:
-  // Timestamp note:
-  //   All timestamps in this unittest are expressed in number of seconds since
-  // epoch, 1970-01-01T00:00:00Z (UTC). The RTCCertificate interface uses ms,
-  // but only seconds-precision is supported by SSLCertificate. To make the
-  // tests clearer we convert everything to seconds since the precision matters
-  // when generating certificates or comparing timestamps.
-  //   As a result, ExpiresSeconds and HasExpiredSeconds are used instead of
-  // RTCCertificate::Expires and ::HasExpired for ms -> s conversion.
-
-  uint64_t NowSeconds() const {
-    return TimeNanos() / kNumNanosecsPerSec;
-  }
-
-  uint64_t ExpiresSeconds(const scoped_refptr<RTCCertificate>& cert) const {
-    uint64_t exp_ms = cert->Expires();
-    uint64_t exp_s = exp_ms / kNumMillisecsPerSec;
-    // Make sure this did not result in loss of precision.
-    RTC_CHECK_EQ(exp_s * kNumMillisecsPerSec, exp_ms);
-    return exp_s;
-  }
-
-  bool HasExpiredSeconds(const scoped_refptr<RTCCertificate>& cert,
-                         uint64_t now_s) const {
-    return cert->HasExpired(now_s * kNumMillisecsPerSec);
-  }
-
-  // An RTC_CHECK ensures that |expires_s| this is in valid range of time_t as
-  // is required by SSLIdentityParams. On some 32-bit systems time_t is limited
-  // to < 2^31. On such systems this will fail for expiration times of year 2038
-  // or later.
-  scoped_refptr<RTCCertificate> GenerateCertificateWithExpires(
-      uint64_t expires_s) const {
-    RTC_CHECK(IsValueInRangeForNumericType<time_t>(expires_s));
-
-    SSLIdentityParams params;
-    params.common_name = kTestCertCommonName;
-    params.not_before = 0;
-    params.not_after = static_cast<time_t>(expires_s);
-    // Certificate type does not matter for our purposes, using ECDSA because it
-    // is fast to generate.
-    params.key_params = KeyParams::ECDSA();
-
-    scoped_ptr<SSLIdentity> identity(SSLIdentity::GenerateForTest(params));
-    return RTCCertificate::Create(identity.Pass());
-  }
-};
-
-TEST_F(RTCCertificateTest, NewCertificateNotExpired) {
-  // Generate a real certificate without specifying the expiration time.
-  // Certificate type doesn't matter, using ECDSA because it's fast to generate.
-  scoped_ptr<SSLIdentity> identity(
-      SSLIdentity::Generate(kTestCertCommonName, KeyParams::ECDSA()));
-  scoped_refptr<RTCCertificate> certificate =
-      RTCCertificate::Create(identity.Pass());
-
-  uint64_t now = NowSeconds();
-  EXPECT_FALSE(HasExpiredSeconds(certificate, now));
-  // Even without specifying the expiration time we would expect it to be valid
-  // for at least half an hour.
-  EXPECT_FALSE(HasExpiredSeconds(certificate, now + 30*60));
-}
-
-TEST_F(RTCCertificateTest, UsesExpiresAskedFor) {
-  uint64_t now = NowSeconds();
-  scoped_refptr<RTCCertificate> certificate =
-      GenerateCertificateWithExpires(now);
-  EXPECT_EQ(now, ExpiresSeconds(certificate));
-}
-
-TEST_F(RTCCertificateTest, ExpiresInOneSecond) {
-  // Generate a certificate that expires in 1s.
-  uint64_t now = NowSeconds();
-  scoped_refptr<RTCCertificate> certificate =
-      GenerateCertificateWithExpires(now + 1);
-  // Now it should not have expired.
-  EXPECT_FALSE(HasExpiredSeconds(certificate, now));
-  // In 2s it should have expired.
-  EXPECT_TRUE(HasExpiredSeconds(certificate, now + 2));
-}
-
-}  // namespace rtc
diff --git a/webrtc/base/sslidentity.h b/webrtc/base/sslidentity.h
index a143ee4108..b8063cee15 100644
--- a/webrtc/base/sslidentity.h
+++ b/webrtc/base/sslidentity.h
@@ -70,8 +70,7 @@ class SSLCertificate {
                              size_t size,
                              size_t* length) const = 0;
 
-  // Returns the time in seconds relative to epoch, 1970-01-01T00:00:00Z (UTC),
-  // or -1 if an expiration time could not be retrieved.
+  // Returns the time in seconds relative to epoch.
   virtual int64_t CertificateExpirationTime() const = 0;
 };