Export of internal Abseil changes.

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7fb969986d7d5a1b30233a94ae7ea29e1abf8937 by Greg Falcon <gfalcon@google.com>:

Fix whitespace in str_join.h.

PiperOrigin-RevId: 208082852

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85428003a8a29fbcd92c0b48708a69460eeb0e8f by Abseil Team <absl-team@google.com>:

Add missing back-ticks to the comments.

PiperOrigin-RevId: 207985417

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0bbac248d5649ac1d7bc71ff1025a11332fb2026 by Abseil Team <absl-team@google.com>:

Internal change.

PiperOrigin-RevId: 207927484

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f587324b99570b403b4626fb03fce16f0d950b05 by Abseil Team <absl-team@google.com>:

Update BaseCountedInstance to have comparison operators and allow them to be tracked by InstanceTracker.

PiperOrigin-RevId: 207919218

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d7f410e4f15328412941f16e25ba3735d5bdfda6 by Derek Mauro <dmauro@google.com>:

Internal import of GitHub PR #153
Removed "warning treated as error" flag from MSVC

PiperOrigin-RevId: 207908806

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59eefc78f8571ffc51cb636894015ce2580508d7 by Abseil Team <absl-team@google.com>:

Fix namespace references in examples from 'std::' to 'absl::'.

PiperOrigin-RevId: 207895230

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151df17b6544222e29913b034a1296c0e14374d5 by Abseil Team <absl-team@google.com>:

Internal Change

PiperOrigin-RevId: 207894949
GitOrigin-RevId: 7fb969986d7d5a1b30233a94ae7ea29e1abf8937
Change-Id: I00097afbe9610ddb3f2330a2a86dcffde7bb6675

3 files changed, 70 insertions, 5 deletions

diff --git a/absl/container/internal/test_instance_tracker.cc b/absl/container/internal/test_instance_tracker.cc
index fe00aca8..b18e0bb7 100644
--- a/absl/container/internal/test_instance_tracker.cc
+++ b/absl/container/internal/test_instance_tracker.cc
@@ -21,6 +21,7 @@ int BaseCountedInstance::num_live_instances_ = 0;
 int BaseCountedInstance::num_moves_ = 0;
 int BaseCountedInstance::num_copies_ = 0;
 int BaseCountedInstance::num_swaps_ = 0;
+int BaseCountedInstance::num_comparisons_ = 0;
 
 }  // namespace test_internal
 }  // namespace absl
diff --git a/absl/container/internal/test_instance_tracker.h b/absl/container/internal/test_instance_tracker.h
index cf8f3a53..ec45f574 100644
--- a/absl/container/internal/test_instance_tracker.h
+++ b/absl/container/internal/test_instance_tracker.h
@@ -22,8 +22,8 @@ namespace absl {
 namespace test_internal {
 
 // A type that counts number of occurences of the type, the live occurrences of
-// the type, as well as the number of copies, moves, and swaps that have
-// occurred on the type. This is used as a base class for the copyable,
+// the type, as well as the number of copies, moves, swaps, and comparisons that
+// have occurred on the type. This is used as a base class for the copyable,
 // copyable+movable, and movable types below that are used in actual tests. Use
 // InstanceTracker in tests to track the number of instances.
 class BaseCountedInstance {
@@ -66,6 +66,36 @@ class BaseCountedInstance {
     return *this;
   }
 
+  bool operator==(const BaseCountedInstance& x) const {
+    ++num_comparisons_;
+    return value_ == x.value_;
+  }
+
+  bool operator!=(const BaseCountedInstance& x) const {
+    ++num_comparisons_;
+    return value_ != x.value_;
+  }
+
+  bool operator<(const BaseCountedInstance& x) const {
+    ++num_comparisons_;
+    return value_ < x.value_;
+  }
+
+  bool operator>(const BaseCountedInstance& x) const {
+    ++num_comparisons_;
+    return value_ > x.value_;
+  }
+
+  bool operator<=(const BaseCountedInstance& x) const {
+    ++num_comparisons_;
+    return value_ <= x.value_;
+  }
+
+  bool operator>=(const BaseCountedInstance& x) const {
+    ++num_comparisons_;
+    return value_ >= x.value_;
+  }
+
   int value() const {
     if (!is_live_) std::abort();
     return value_;
@@ -108,6 +138,9 @@ class BaseCountedInstance {
 
   // Number of times that BaseCountedInstance objects were swapped.
   static int num_swaps_;
+
+  // Number of times that BaseCountedInstance objects were compared.
+  static int num_comparisons_;
 };
 
 // Helper to track the BaseCountedInstance instance counters. Expects that the
@@ -152,13 +185,21 @@ class InstanceTracker {
   // construction or the last call to ResetCopiesMovesSwaps().
   int swaps() const { return BaseCountedInstance::num_swaps_ - start_swaps_; }
 
-  // Resets the base values for moves, copies and swaps to the current values,
-  // so that subsequent Get*() calls for moves, copies and swaps will compare to
-  // the situation at the point of this call.
+  // Returns the number of comparisons on BaseCountedInstance objects since
+  // construction or the last call to ResetCopiesMovesSwaps().
+  int comparisons() const {
+    return BaseCountedInstance::num_comparisons_ - start_comparisons_;
+  }
+
+  // Resets the base values for moves, copies, comparisons, and swaps to the
+  // current values, so that subsequent Get*() calls for moves, copies,
+  // comparisons, and swaps will compare to the situation at the point of this
+  // call.
   void ResetCopiesMovesSwaps() {
     start_moves_ = BaseCountedInstance::num_moves_;
     start_copies_ = BaseCountedInstance::num_copies_;
     start_swaps_ = BaseCountedInstance::num_swaps_;
+    start_comparisons_ = BaseCountedInstance::num_comparisons_;
   }
 
  private:
@@ -167,6 +208,7 @@ class InstanceTracker {
   int start_moves_;
   int start_copies_;
   int start_swaps_;
+  int start_comparisons_;
 };
 
 // Copyable, not movable.
diff --git a/absl/container/internal/test_instance_tracker_test.cc b/absl/container/internal/test_instance_tracker_test.cc
index 9efb6771..0ae57636 100644
--- a/absl/container/internal/test_instance_tracker_test.cc
+++ b/absl/container/internal/test_instance_tracker_test.cc
@@ -157,4 +157,26 @@ TEST(TestInstanceTracker, ExistingInstances) {
   EXPECT_EQ(1, tracker.moves());
 }
 
+TEST(TestInstanceTracker, Comparisons) {
+  InstanceTracker tracker;
+  MovableOnlyInstance one(1), two(2);
+
+  EXPECT_EQ(0, tracker.comparisons());
+  EXPECT_FALSE(one == two);
+  EXPECT_EQ(1, tracker.comparisons());
+  EXPECT_TRUE(one != two);
+  EXPECT_EQ(2, tracker.comparisons());
+  EXPECT_TRUE(one < two);
+  EXPECT_EQ(3, tracker.comparisons());
+  EXPECT_FALSE(one > two);
+  EXPECT_EQ(4, tracker.comparisons());
+  EXPECT_TRUE(one <= two);
+  EXPECT_EQ(5, tracker.comparisons());
+  EXPECT_FALSE(one >= two);
+  EXPECT_EQ(6, tracker.comparisons());
+
+  tracker.ResetCopiesMovesSwaps();
+  EXPECT_EQ(0, tracker.comparisons());
+}
+
 }  // namespace