Export of internal Abseil changes

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93c607726d663800b4bfa472cba043fd3f5d0e97 by Derek Mauro <dmauro@google.com>:

Internal change

PiperOrigin-RevId: 389158822

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55b3bb50bbc168567c6ba25d07df2c2c39e864af by Martijn Vels <mvels@google.com>:

Change CordRepRing alternative implementation to CordRepBtree alternative.

This changes makes CordRepBtree (BTREE) the alternative to CordRepConcat (CONCAT) trees, enabled through the internal / experimental 'cord_btree_enabled' latch.

PiperOrigin-RevId: 389030571

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d6fc346143606c096bca8eb5029e4c429ac6e305 by Todd Lipcon <tlipcon@google.com>:

Fix a small typo in SequenceLock doc comment

PiperOrigin-RevId: 388972936

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e46f9245dce8b4150e3ca2664e0cf42b75f90a83 by Martijn Vels <mvels@google.com>:

Add 'shallow' validation mode to CordRepBtree which will be the default for internal assertions.

PiperOrigin-RevId: 388753606

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b5e74f163b490beb006f848ace67bb650433fe13 by Martijn Vels <mvels@google.com>:

Add btree statistics to CordzInfo, and reduce rounding errors

PiperOrigin-RevId: 388715878

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105bcbf80de649937e693b29b18220f9e6841a51 by Evan Brown <ezb@google.com>:

Skip length checking when constructing absl::string_view from `const char*`.
The length check causes unnecessary code bloat.

PiperOrigin-RevId: 388271741

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bed595158f24839efe49c65ae483f797d79fe0ae by Derek Mauro <dmauro@google.com>:

Internal change

PiperOrigin-RevId: 387713428
GitOrigin-RevId: 93c607726d663800b4bfa472cba043fd3f5d0e97
Change-Id: I2a4840f5ffcd7f70b7d7d45cce66f23c42cf565f

1 files changed, 3 insertions, 0 deletions

diff --git a/absl/strings/internal/cordz_statistics.h b/absl/strings/internal/cordz_statistics.h
index e03c651e..da4c7dbb 100644
--- a/absl/strings/internal/cordz_statistics.h
+++ b/absl/strings/internal/cordz_statistics.h
@@ -40,6 +40,7 @@ struct CordzStatistics {
     size_t substring = 0;  // #substring reps
     size_t concat = 0;     // #concat reps
     size_t ring = 0;       // #ring buffer reps
+    size_t btree = 0;      // #btree reps
   };
 
   // The size of the cord in bytes. This matches the result of Cord::size().
@@ -61,6 +62,8 @@ struct CordzStatistics {
 
   // The total number of nodes referenced by this cord.
   // For ring buffer Cords, this includes the 'ring buffer' node.
+  // For btree Cords, this includes all 'CordRepBtree' tree nodes as well as all
+  // the substring, flat and external nodes referenced by the tree.
   // A value of 0 implies the property has not been recorded.
   int64_t node_count = 0;