merge(3p/absl): subtree merge of Abseil up to e19260f r/1889

... notably, this includes Abseil's own StatusOr type, which
conflicted with our implementation (that was taken from TensorFlow).

Change-Id: Ie7d6764b64055caaeb8dc7b6b9d066291e6b538f

1 files changed, 7 insertions, 2 deletions

diff --git a/third_party/abseil_cpp/absl/flags/reflection.h b/third_party/abseil_cpp/absl/flags/reflection.h
index 045f9784e269..e6baf5de4b0c 100644
--- a/third_party/abseil_cpp/absl/flags/reflection.h
+++ b/third_party/abseil_cpp/absl/flags/reflection.h
@@ -26,6 +26,7 @@
 #include <string>
 
 #include "absl/base/config.h"
+#include "absl/container/flat_hash_map.h"
 #include "absl/flags/commandlineflag.h"
 #include "absl/flags/internal/commandlineflag.h"
 
@@ -40,7 +41,11 @@ class FlagSaverImpl;
 // Returns the reflection handle of an Abseil flag of the specified name, or
 // `nullptr` if not found. This function will emit a warning if the name of a
 // 'retired' flag is specified.
-CommandLineFlag* FindCommandLineFlag(absl::string_view name);
+absl::CommandLineFlag* FindCommandLineFlag(absl::string_view name);
+
+// Returns current state of the Flags registry in a form of mapping from flag
+// name to a flag reflection handle.
+absl::flat_hash_map<absl::string_view, absl::CommandLineFlag*> GetAllFlags();
 
 //------------------------------------------------------------------------------
 // FlagSaver
@@ -59,7 +64,7 @@ CommandLineFlag* FindCommandLineFlag(absl::string_view name);
 //   void MyFunc() {
 //    absl::FlagSaver fs;
 //    ...
-//    absl::SetFlag(FLAGS_myFlag, otherValue);
+//    absl::SetFlag(&FLAGS_myFlag, otherValue);
 //    ...
 //  } // scope of FlagSaver left, flags return to previous state
 //