Change EXPECT/ASSERT_DCHECK_DEATH macro to not expose the |regex| parameter.

base/metrics/histogram_unittest.cc

Index: base/metrics/histogram_unittest.cc
diff --git a/base/metrics/histogram_unittest.cc b/base/metrics/histogram_unittest.cc
index ccfe103c60bfb2cec4270141ba5e3f492b78338e..674b9125c095bb31d645cf47bae642fe408ad865 100644
--- a/base/metrics/histogram_unittest.cc
+++ b/base/metrics/histogram_unittest.cc
@@ -737,16 +737,14 @@ TEST(HistogramDeathTest, BadRangesTest) {
   custom_ranges.push_back(HistogramBase::kSampleType_MAX);
   EXPECT_DCHECK_DEATH(
       CustomHistogram::FactoryGet("BadRangesCustom2", custom_ranges,
-                                  HistogramBase::kNoFlags),
-      "");
+                                  HistogramBase::kNoFlags));
 
   // CustomHistogram needs at least 1 valid range.
   custom_ranges.clear();
   custom_ranges.push_back(0);
   EXPECT_DCHECK_DEATH(
       CustomHistogram::FactoryGet("BadRangesCustom3", custom_ranges,
-                                  HistogramBase::kNoFlags),
-      "");
+                                  HistogramBase::kNoFlags));
 }
 
 }  // namespace base