Consume result from various SampleRecorder methods.

PiperOrigin-RevId: 897903309
Change-Id: I944031c84f2bcc6c116cef750ce789381b134467

absl/container/internal/hashtablez_sampler_test.cc

diff --git a/absl/container/internal/hashtablez_sampler_test.cc b/absl/container/internal/hashtablez_sampler_test.cc
index c313693..ae89c02 100644
--- a/absl/container/internal/hashtablez_sampler_test.cc
+++ b/absl/container/internal/hashtablez_sampler_test.cc
@@ -63,9 +63,10 @@
 
 std::vector<size_t> GetSizes(HashtablezSampler* s) {
   std::vector<size_t> res;
-  s->Iterate([&](const HashtablezInfo& info) {
+  EXPECT_EQ(s->Iterate([&](const HashtablezInfo& info) {
     res.push_back(info.size.load(std::memory_order_acquire));
-  });
+  }),
+            0);
   return res;
 }
 
@@ -359,19 +360,20 @@
   info->hashes_bitwise_and.store(0x12345678, std::memory_order_relaxed);
 
   bool found = false;
-  sampler.Iterate([&](const HashtablezInfo& h) {
+  EXPECT_EQ(sampler.Iterate([&](const HashtablezInfo& h) {
     if (&h == info) {
       EXPECT_EQ(h.weight, test_stride);
       EXPECT_EQ(h.hashes_bitwise_and.load(), 0x12345678);
       found = true;
     }
-  });
+  }),
+            0);
   EXPECT_TRUE(found);
 
   h.Unregister();
   h = HashtablezInfoHandle();
   found = false;
-  sampler.Iterate([&](const HashtablezInfo& h) {
+  EXPECT_EQ(sampler.Iterate([&](const HashtablezInfo& h) {
     if (&h == info) {
       // this will only happen if some other thread has resurrected the info
       // the old handle was using.
@@ -379,7 +381,8 @@
         found = true;
       }
     }
-  });
+  }),
+            0);
   EXPECT_FALSE(found);
 }
 #endif
@@ -465,9 +468,10 @@
           }
           case 2: {
             absl::Duration oldest = absl::ZeroDuration();
-            sampler.Iterate([&](const HashtablezInfo& info) {
+            EXPECT_EQ(sampler.Iterate([&](const HashtablezInfo& info) {
               oldest = std::max(oldest, absl::Now() - info.create_time);
-            });
+            }),
+                      0);
             ASSERT_GE(oldest, absl::ZeroDuration());
             break;
           }

absl/container/sample_element_size_test.cc

diff --git a/absl/container/sample_element_size_test.cc b/absl/container/sample_element_size_test.cc
index ccc616f..9ce19fe 100644
--- a/absl/container/sample_element_size_test.cc
+++ b/absl/container/sample_element_size_test.cc
@@ -57,12 +57,13 @@
     tables.back().insert(values.begin(), values.end());
   }
   size_t new_count = 0;
-  sampler.Iterate([&](const HashtablezInfo& info) {
+  EXPECT_EQ(sampler.Iterate([&](const HashtablezInfo& info) {
     if (preexisting_info.insert(&info).second) {
       EXPECT_EQ(info.inline_element_size, expected_element_size);
       ++new_count;
     }
-  });
+  }),
+            0);
   // Make sure we actually did get a new hashtablez.
   EXPECT_GT(new_count, 0);
 }
@@ -99,8 +100,10 @@
   // cannot be a flat_hash_set, however, since that would introduce a mutex
   // deadlock.
   std::unordered_set<const HashtablezInfo*> preexisting_info;  // NOLINT
-  sampler.Iterate(
-      [&](const HashtablezInfo& info) { preexisting_info.insert(&info); });
+  EXPECT_EQ(sampler.Iterate([&](const HashtablezInfo& info) {
+    preexisting_info.insert(&info);
+  }),
+            0);
   TestInlineElementSize(sampler, preexisting_info, flat_map_tables, map_values,
                         sizeof(int) + sizeof(bigstruct));
   TestInlineElementSize(sampler, preexisting_info, node_map_tables, map_values,

absl/profiling/internal/sample_recorder_test.cc

diff --git a/absl/profiling/internal/sample_recorder_test.cc b/absl/profiling/internal/sample_recorder_test.cc
index a037f9d..31c72ed 100644
--- a/absl/profiling/internal/sample_recorder_test.cc
+++ b/absl/profiling/internal/sample_recorder_test.cc
@@ -49,15 +49,17 @@
 
 std::vector<size_t> GetSizes(SampleRecorder<Info>* s) {
   std::vector<size_t> res;
-  s->Iterate([&](const Info& info) {
+  EXPECT_EQ(s->Iterate([&](const Info& info) {
     res.push_back(info.size.load(std::memory_order_acquire));
-  });
+  }),
+            0);
   return res;
 }
 
 std::vector<int64_t> GetWeights(SampleRecorder<Info>* s) {
   std::vector<int64_t> res;
-  s->Iterate([&](const Info& info) { res.push_back(info.weight); });
+  EXPECT_EQ(s->Iterate([&](const Info& info) { res.push_back(info.weight); }),
+            0);
   return res;
 }
 
@@ -141,9 +143,10 @@
           }
           case 2: {
             absl::Duration oldest = absl::ZeroDuration();
-            sampler.Iterate([&](const Info& info) {
+            EXPECT_EQ(sampler.Iterate([&](const Info& info) {
               oldest = std::max(oldest, absl::Now() - info.create_time);
-            });
+            }),
+                      0);
             ASSERT_GE(oldest, absl::ZeroDuration());
             break;
           }