Implement Dump-on-DCHECK (via a new LogSeverity).

base/metrics/sample_vector_unittest.cc

Index: base/metrics/sample_vector_unittest.cc
diff --git a/base/metrics/sample_vector_unittest.cc b/base/metrics/sample_vector_unittest.cc
index 0abacad84be82784efbc0627e8b507c577f44ed3..2d77d2376b83a7442fd2e0929e5e21d832d6ba88 100644
--- a/base/metrics/sample_vector_unittest.cc
+++ b/base/metrics/sample_vector_unittest.cc
@@ -116,7 +116,6 @@ TEST(SampleVectorTest, AddSubtractTest) {
   EXPECT_EQ(samples1.redundant_count(), samples1.TotalCount());
 }
 
-#if (!defined(NDEBUG) || defined(DCHECK_ALWAYS_ON)) && GTEST_HAS_DEATH_TEST
 TEST(SampleVectorDeathTest, BucketIndexTest) {
   // 8 buckets with exponential layout:
   // [0, 1) [1, 2) [2, 4) [4, 8) [8, 16) [16, 32) [32, 64) [64, INT_MAX)
@@ -133,9 +132,9 @@ TEST(SampleVectorDeathTest, BucketIndexTest) {
   EXPECT_EQ(3, samples.GetCount(65));
 
   // Extreme case.
-  EXPECT_DEATH(samples.Accumulate(INT_MIN, 100), "");
-  EXPECT_DEATH(samples.Accumulate(-1, 100), "");
-  EXPECT_DEATH(samples.Accumulate(INT_MAX, 100), "");
+  EXPECT_DCHECK_DEATH(samples.Accumulate(INT_MIN, 100));
+  EXPECT_DCHECK_DEATH(samples.Accumulate(-1, 100));
+  EXPECT_DCHECK_DEATH(samples.Accumulate(INT_MAX, 100));

[Wez, 2016/12/19 23:57:46]

Q: Having DCHECK death-tests run but trivially pass doesn't seem helpful.  Can
we instead update the test infrastructure to be aware of death-tests and
DCHECK-tests - e.g:

DEATH_FooTest -> Run only if death tests are supported.
DCHECK_DEATH_FooTest -> Run only if DCHECK causes death on failure.

We could alternatively implement that via macros:

#define DCHECK_DEATH_NAME(test) ...

but that does make test names annoyingly verbose.

 
   // Custom buckets: [1, 5) [5, 10)
   // Note, this is not a valid BucketRanges for Histogram because it does not
@@ -155,8 +154,8 @@ TEST(SampleVectorDeathTest, BucketIndexTest) {
   EXPECT_EQ(4, samples2.GetCount(5));
 
   // Extreme case.
-  EXPECT_DEATH(samples2.Accumulate(0, 100), "");
-  EXPECT_DEATH(samples2.Accumulate(10, 100), "");
+  EXPECT_DCHECK_DEATH(samples2.Accumulate(0, 100));
+  EXPECT_DCHECK_DEATH(samples2.Accumulate(10, 100));
 }
 
 TEST(SampleVectorDeathTest, AddSubtractBucketNotMatchTest) {
@@ -182,25 +181,22 @@ TEST(SampleVectorDeathTest, AddSubtractBucketNotMatchTest) {
 
   // Extra bucket in the beginning.
   samples2.Accumulate(0, 100);
-  EXPECT_DEATH(samples1.Add(samples2), "");
-  EXPECT_DEATH(samples1.Subtract(samples2), "");
+  EXPECT_DCHECK_DEATH(samples1.Add(samples2));
+  EXPECT_DCHECK_DEATH(samples1.Subtract(samples2));
 
   // Extra bucket in the end.
   samples2.Accumulate(0, -100);
   samples2.Accumulate(6, 100);
-  EXPECT_DEATH(samples1.Add(samples2), "");
-  EXPECT_DEATH(samples1.Subtract(samples2), "");
+  EXPECT_DCHECK_DEATH(samples1.Add(samples2));
+  EXPECT_DCHECK_DEATH(samples1.Subtract(samples2));
 
   // Bucket not match: [3, 5) VS [3, 6)
   samples2.Accumulate(6, -100);
   samples2.Accumulate(3, 100);
-  EXPECT_DEATH(samples1.Add(samples2), "");
-  EXPECT_DEATH(samples1.Subtract(samples2), "");
+  EXPECT_DCHECK_DEATH(samples1.Add(samples2));
+  EXPECT_DCHECK_DEATH(samples1.Subtract(samples2));
 }
 
-#endif
-// (!defined(NDEBUG) || defined(DCHECK_ALWAYS_ON)) && GTEST_HAS_DEATH_TEST
-
 TEST(SampleVectorIteratorTest, IterateTest) {
   BucketRanges ranges(5);
   ranges.set_range(0, 0);