Implement Dump-on-DCHECK (via alternate DCHECK and DCHECK_OP macro implementations).

base/logging_unittest.cc

Index: base/logging_unittest.cc
diff --git a/base/logging_unittest.cc b/base/logging_unittest.cc
index 16c89cf76fced5d9f95464e42d7455dbb4c2f78d..3638b4a68382aa20a67e22f05582585eb4abd5d6 100644
--- a/base/logging_unittest.cc
+++ b/base/logging_unittest.cc
@@ -4,6 +4,7 @@
 
 #include "base/logging.h"
 #include "base/compiler_specific.h"
+#include "base/debug/dump_without_crashing.h"
 #include "base/macros.h"
 
 #include "testing/gmock/include/gmock/gmock.h"
@@ -101,7 +102,7 @@ TEST_F(LoggingTest, BasicLogging) {
 }
 
 TEST_F(LoggingTest, LogIsOn) {
-#if defined(NDEBUG)
+#if defined(NDEBUG) || defined(DCHECK_IS_DUMP_WITHOUT_CRASH)
   const bool kDfatalIsFatal = false;
 #else  // defined(NDEBUG)
   const bool kDfatalIsFatal = true;
@@ -380,6 +381,7 @@ TEST_F(LoggingTest, DcheckStreamsAreLazy) {
 #endif
 }
 
+#if !defined(DCHECK_IS_DUMP_WITHOUT_CRASH)
 void DcheckEmptyFunction1() {
   // Provide a body so that Release builds do not cause the compiler to
   // optimize DcheckEmptyFunction1 and DcheckEmptyFunction2 as a single
@@ -455,6 +457,7 @@ TEST_F(LoggingTest, Dcheck) {
   DCHECK_EQ(mp2, &MemberFunctions::MemberFunction1);
   EXPECT_EQ(DCHECK_IS_ON() ? 2 : 0, g_log_sink_call_count);
 }
+#endif  // !defined(DCHECK_IS_DUMP_WITHOUT_CRASH)
 
 TEST_F(LoggingTest, DcheckReleaseBehavior) {
   int some_variable = 1;
@@ -489,6 +492,32 @@ TEST_F(LoggingTest, CheckEqStatements) {
     CHECK_EQ(false, true);           // Unreached.
 }
 
+#if defined(DCHECK_IS_DUMP_WITHOUT_CRASH)
+namespace {
+
+int g_fake_dump_without_crashing_count = 0;
+void FakeDumpWithoutCrashing() {
+  g_fake_dump_without_crashing_count++;
+}
+
+}  // namespace
+
+TEST_F(LoggingTest, DCheckIsDumpWithoutCrash) {
+  // Replace the dump-without-crashing function, to test.
+  base::debug::SetDumpWithoutCrashingFunction(&FakeDumpWithoutCrashing);
+
+  // Invoke DCHECK(false) twice, and verify that only one dump call is made.
+  DCHECK(false);
+  EXPECT_EQ(1, g_fake_dump_without_crashing_count);
+  DCHECK(false);
+  EXPECT_EQ(1, g_fake_dump_without_crashing_count);
+
+  EXPECT_EQ(LOG_ERROR, LOG_DFATAL);
+
+  base::debug::SetDumpWithoutCrashingFunction(nullptr);
+}
+#endif  // defined(DCHECK_IS_DUMP_WITHOUT_CRASH)
+
 // Test that defining an operator<< for a type in a namespace doesn't prevent
 // other code in that namespace from calling the operator<<(ostream, wstring)
 // defined by logging.h. This can fail if operator<<(ostream, wstring) can't be