Change dont_embed_build_metadata default to 1 except for Official build and fix some unittests.

FieldTrialTest.DisableProbability was using Time::NowFromSystemTime - 1 year to generate a date before the build time. Instead use GetBuildTime - 1 year.

TransportSecurityState::IsBuildTimely is using GetBuildTime to determine if the build is older than 10 weeks. Disable this and return a default value if DONT_EMBED_BUILD_METADATA is defined (i.e. The build time is invalid) and we're not doing an official build.

CL based on https://codereview.chromium.org/685123005/ with some additional fixes for the unittests.

BUG=314403

Review URL: https://codereview.chromium.org/695523002

Cr-Commit-Position: refs/heads/master@{#302316}

6 files changed, 38 insertions, 10 deletions

diff --git a/base/build_time.cc b/base/build_time.cc
index 86503e2..b8b4296 100644
--- a/base/build_time.cc
+++ b/base/build_time.cc
@@ -16,7 +16,7 @@ Time GetBuildTime() {
   //
   // __DATE__ is exactly "Mmm DD YYYY".
   // __TIME__ is exactly "hh:mm:ss".
-#if defined(DONT_EMBED_BUILD_METADATA)
+#if defined(DONT_EMBED_BUILD_METADATA) && !defined(OFFICIAL_BUILD)
   const char kDateTime[] = "Sep 02 2008 08:00:00 PST";
 #else
   const char kDateTime[] = __DATE__ " " __TIME__ " PST";
diff --git a/base/build_time.h b/base/build_time.h
index 73c01b0..c7df479 100644
--- a/base/build_time.h
+++ b/base/build_time.h
@@ -18,6 +18,9 @@ namespace base {
 //
 // Also, since __TIME__ doesn't include a timezone, this value should only be
 // considered accurate to a day.
+//
+// NOTE: This function is disabled except for the official builds, by default
+// the date returned is "Sep 02 2008 08:00:00 PST".
 Time BASE_EXPORT GetBuildTime();
 
 }  // namespace base
diff --git a/base/metrics/field_trial_unittest.cc b/base/metrics/field_trial_unittest.cc
index 80c729d..1ed3f89 100644
--- a/base/metrics/field_trial_unittest.cc
+++ b/base/metrics/field_trial_unittest.cc
@@ -4,6 +4,7 @@
 
 #include "base/metrics/field_trial.h"
 
+#include "base/build_time.h"
 #include "base/message_loop/message_loop.h"
 #include "base/rand_util.h"
 #include "base/run_loop.h"
@@ -30,10 +31,10 @@ scoped_refptr<base::FieldTrial> CreateFieldTrial(
       base::FieldTrial::SESSION_RANDOMIZED, default_group_number);
 }
 
-int GetLastYear() {
-  Time last_year_time = Time::NowFromSystemTime() - TimeDelta::FromDays(365);
+int OneYearBeforeBuildTime() {
+  Time one_year_before_build_time = GetBuildTime() - TimeDelta::FromDays(365);
   Time::Exploded exploded;
-  last_year_time.LocalExplode(&exploded);
+  one_year_before_build_time.LocalExplode(&exploded);
   return exploded.year;
 }
 
@@ -249,7 +250,7 @@ TEST_F(FieldTrialTest, DisableProbability) {
   // Create a field trail that has expired.
   int default_group_number = -1;
   FieldTrial* trial = FieldTrialList::FactoryGetFieldTrial(
-      name, 1000000000, default_group_name, GetLastYear(), 1, 1,
+      name, 1000000000, default_group_name, OneYearBeforeBuildTime(), 1, 1,
       FieldTrial::SESSION_RANDOMIZED,
       &default_group_number);
   trial->AppendGroup(loser, 999999999);  // 99.9999999% chance of being chosen.
diff --git a/build/common.gypi b/build/common.gypi
index d7a664b..62d803d 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -308,11 +308,10 @@
       # on compile-only bots).
       'fastbuild%': 0,
 
-      # Set to 1 to not store any build metadata (this isn't working yet but
-      # this flag will help us to get there). See http://crbug.com/314403.
-      # TODO(sebmarchand): Update this comment once this flag guarantee that
-      #     there's no build metadata in the build artifacts.
-      'dont_embed_build_metadata%': 0,
+      # Set to 1 to not store any build metadata, e.g. ifdef out all __DATE__
+      # and __TIME__. Set to 0 to reenable the use of these macros in the code
+      # base. See http://crbug.com/314403.
+      'dont_embed_build_metadata%': 1,
 
       # Set to 1 to force Visual C++ to use legacy debug information format /Z7.
       # This is useful for parallel compilation tools which can't support /Zi.
@@ -1499,6 +1498,14 @@
     'ozone_platform_test%': 0,
 
     'conditions': [
+      ['buildtype=="Official"', {
+        # Continue to embed build meta data in Official builds, basically the
+        # time it was built.
+        # TODO(maruel): This decision should be revisited because having an
+        # official deterministic build has high value too but MSVC toolset can't
+        # generate anything deterministic with WPO enabled AFAIK.
+        'dont_embed_build_metadata%': 0,
+      }],
       # Enable the Syzygy optimization step for the official builds.
       ['OS=="win" and buildtype=="Official" and syzyasan!=1', {
         'syzygy_optimize%': 1,
diff --git a/chrome/browser/ssl/ssl_error_classification.cc b/chrome/browser/ssl/ssl_error_classification.cc
index 12983f5..cddbfb0 100644
--- a/chrome/browser/ssl/ssl_error_classification.cc
+++ b/chrome/browser/ssl/ssl_error_classification.cc
@@ -353,18 +353,26 @@ float SSLErrorClassification::CalculateScoreEnvironments() const {
 }
 
 bool SSLErrorClassification::IsUserClockInThePast(const base::Time& time_now) {
+#if defined(DONT_EMBED_BUILD_METADATA) && !defined(OFFICIAL_BUILD)
+  return false;
+#else
   base::Time build_time = base::GetBuildTime();
   if (time_now < build_time - base::TimeDelta::FromDays(2))
     return true;
   return false;
+#endif
 }
 
 bool SSLErrorClassification::IsUserClockInTheFuture(
     const base::Time& time_now) {
+#if defined(DONT_EMBED_BUILD_METADATA) && !defined(OFFICIAL_BUILD)
+  return false;
+#else
   base::Time build_time = base::GetBuildTime();
   if (time_now > build_time + base::TimeDelta::FromDays(365))
     return true;
   return false;
+#endif
 }
 
 bool SSLErrorClassification::MaybeWindowsLacksSHA256Support() {
diff --git a/net/http/transport_security_state.cc b/net/http/transport_security_state.cc
index d0c0b33..907e6d8 100644
--- a/net/http/transport_security_state.cc
+++ b/net/http/transport_security_state.cc
@@ -721,9 +721,18 @@ void TransportSecurityState::ReportUMAOnPinFailure(const std::string& host) {
 
 // static
 bool TransportSecurityState::IsBuildTimely() {
+  // If the build metadata aren't embedded in the binary then we can't use the
+  // build time to determine if the build is timely, return true by default. If
+  // we're building an official build then keep using the build time, even if
+  // it's invalid it'd be a date in the past and this function will return
+  // false.
+#if defined(DONT_EMBED_BUILD_METADATA) && !defined(OFFICIAL_BUILD)
+  return true;
+#else
   const base::Time build_time = base::GetBuildTime();
   // We consider built-in information to be timely for 10 weeks.
   return (base::Time::Now() - build_time).InDays() < 70 /* 10 weeks */;
+#endif
 }
 
 bool TransportSecurityState::CheckPublicKeyPinsImpl(