Replace use of logging::DEBUG_MODE with DCHECK_IS_ON().

DEBUG_MODE was originally provided to allow code of the form:

  if (DEBUG_MODE) { ... }

rather than preprocessor conditional (i.e. #ifdef _DEBUG), while
still ensuring that the condition was static at compile-time, allowing
the affected code to be trivially optimized-out.

The function-like macro DCHECK_IS_ON(), added to simplify conditional
compilation of DCHECK-related code when DCHECK_ALWAYS_ON was added, can
now be used safely for both preprocessor and C++ conditionals in place of
DEBUG_MODE.

Review-Url: https://codereview.chromium.org/2731823002
Cr-Commit-Position: refs/heads/master@{#456519}

base/logging.h

@@ -747,13 +747,6 @@ DEFINE_CHECK_OP_IMPL(GT, > )
 
 #endif  // DCHECK_IS_ON()
 
-// DEBUG_MODE is for runtime uses like
-//   if (DEBUG_MODE) foo.CheckThatFoo();
-// We tie its state to DCHECK_IS_ON().
-//
-// For compile-time checks, #if DCHECK_IS_ON() can be used.
-enum { DEBUG_MODE = DCHECK_IS_ON() };
-
 #define DLOG(severity)                                          \
   LAZY_STREAM(LOG_STREAM(severity), DLOG_IS_ON(severity))
 

base/logging_unittest.cc

@@ -69,16 +69,14 @@ class MockLogSource {
 
 TEST_F(LoggingTest, BasicLogging) {
   MockLogSource mock_log_source;
-  EXPECT_CALL(mock_log_source, Log()).Times(DEBUG_MODE ? 16 : 8).
-      WillRepeatedly(Return("log message"));
+  EXPECT_CALL(mock_log_source, Log())
+      .Times(DCHECK_IS_ON() ? 16 : 8)
+      .WillRepeatedly(Return("log message"));
 
   SetMinLogLevel(LOG_INFO);
 
   EXPECT_TRUE(LOG_IS_ON(INFO));
-  // As of g++-4.5, the first argument to EXPECT_EQ cannot be a
-  // constant expression.
-  const bool kIsDebugMode = (DEBUG_MODE != 0);
-  EXPECT_TRUE(kIsDebugMode == DLOG_IS_ON(INFO));
+  EXPECT_TRUE((DCHECK_IS_ON() != 0) == DLOG_IS_ON(INFO));
   EXPECT_TRUE(VLOG_IS_ON(0));
 
   LOG(INFO) << mock_log_source.Log();

components/sync/base/logging.h

@@ -27,7 +27,7 @@ bool VlogIsOnForLocation(const tracked_objects::Location& from_here,
 
 #define DVLOG_LOC(from_here, verbose_level)              \
   LAZY_STREAM(VLOG_LOC_STREAM(from_here, verbose_level), \
-              ::logging::DEBUG_MODE &&                   \
+              DCHECK_IS_ON() &&                          \
                   (VLOG_IS_ON(verbose_level) ||          \
                    ::syncer::VlogIsOnForLocation(from_here, verbose_level)))
 

components/sync/engine_impl/traffic_logger.cc

@@ -21,7 +21,7 @@ void LogData(const T& data,
              std::unique_ptr<base::DictionaryValue> (
                  *to_dictionary_value)(const T&, bool),
              const std::string& description) {
-  if (::logging::DEBUG_MODE && VLOG_IS_ON(1)) {
+  if (DCHECK_IS_ON() && VLOG_IS_ON(1)) {
     std::unique_ptr<base::DictionaryValue> value =
         (*to_dictionary_value)(data, true /* include_specifics */);
     std::string message;

crypto/openssl_util.cc

@@ -40,7 +40,7 @@ void EnsureOpenSSLInit() {
 }
 
 void ClearOpenSSLERRStack(const tracked_objects::Location& location) {
-  if (logging::DEBUG_MODE && VLOG_IS_ON(1)) {
+  if (DCHECK_IS_ON() && VLOG_IS_ON(1)) {
     uint32_t error_num = ERR_peek_error();
     if (error_num == 0)
       return;