Support negative sample values in PersistentHistogramMap.

base/metrics/persistent_sample_map_unittest.cc

Index: base/metrics/persistent_sample_map_unittest.cc
diff --git a/base/metrics/persistent_sample_map_unittest.cc b/base/metrics/persistent_sample_map_unittest.cc
index 48e9900c0987f1780da96c216f3d2d602858b466..f2e41dad8b067819c65f26c55fb4f1b558cceb12 100644
--- a/base/metrics/persistent_sample_map_unittest.cc
+++ b/base/metrics/persistent_sample_map_unittest.cc
@@ -10,7 +10,6 @@
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace base {
-namespace {
 
 TEST(PersistentSampleMapTest, AccumulateTest) {
   LocalPersistentMemoryAllocator allocator(64 << 10, 0, "");  // 64 KiB
@@ -85,6 +84,8 @@ TEST(PersistentSampleMapTest, AddSubtractTest) {
 }
 
 TEST(PersistentSampleMapTest, PersistenceTest) {
+  const int kAllSamples = PersistentSampleMap::kAllSamples;
+
   LocalPersistentMemoryAllocator allocator(64 << 10, 0, "");  // 64 KiB
 
   HistogramSamples::Metadata meta12;
@@ -93,10 +94,12 @@ TEST(PersistentSampleMapTest, PersistenceTest) {
   samples1.Accumulate(1, 100);
   samples1.Accumulate(2, 200);
   samples1.Accumulate(1, -200);
+  samples1.Accumulate(kAllSamples, 1);
   EXPECT_EQ(-100, samples1.GetCount(1));
   EXPECT_EQ(200, samples1.GetCount(2));
-  EXPECT_EQ(300, samples1.sum());
-  EXPECT_EQ(100, samples1.TotalCount());
+  EXPECT_EQ(1, samples1.GetCount(kAllSamples));
+  EXPECT_EQ(300 + kAllSamples, samples1.sum());
+  EXPECT_EQ(101, samples1.TotalCount());
   EXPECT_EQ(samples1.redundant_count(), samples1.TotalCount());
 
   PersistentSparseHistogramDataManager manager2(&allocator);
@@ -107,10 +110,12 @@ TEST(PersistentSampleMapTest, PersistenceTest) {
   EXPECT_EQ(samples1.TotalCount(), samples2.TotalCount());
   EXPECT_EQ(-100, samples2.GetCount(1));
   EXPECT_EQ(200, samples2.GetCount(2));
-  EXPECT_EQ(300, samples2.sum());
-  EXPECT_EQ(100, samples2.TotalCount());
+  EXPECT_EQ(1, samples2.GetCount(kAllSamples));
+  EXPECT_EQ(300 + kAllSamples, samples2.sum());
+  EXPECT_EQ(101, samples2.TotalCount());
   EXPECT_EQ(samples2.redundant_count(), samples2.TotalCount());
 
+  samples1.Accumulate(kAllSamples, -1);
   EXPECT_EQ(0, samples2.GetCount(3));
   EXPECT_EQ(0, samples1.GetCount(3));
   samples2.Accumulate(3, 300);
@@ -244,5 +249,4 @@ TEST(PersistentSampleMapIteratorDeathTest, IterateDoneTest) {
 #endif
 // (!defined(NDEBUG) || defined(DCHECK_ALWAYS_ON)) && GTEST_HAS_DEATH_TEST
 
-}  // namespace
 }  // namespace base