[geolocation] Add a Core Location backend behind a flag

This CL Adds a new Location Provider that uses the Core Location
API to determine Location.

Bug: 1035290
Change-Id: I7cff4285ba10163b7fcc6657c1c8705872526606
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2152105
Commit-Queue: James Hollyer <[email protected]>
Reviewed-by: Ovidio de Jesús Ruiz-Henríquez <[email protected]>
Reviewed-by: Reilly Grant <[email protected]>
Cr-Commit-Position: refs/heads/master@{#765416}
diff --git a/chrome/browser/flag_descriptions.h b/chrome/browser/flag_descriptions.h
index 8673531..f587821 100644
--- a/chrome/browser/flag_descriptions.h
+++ b/chrome/browser/flag_descriptions.h
@@ -387,6 +387,9 @@
 extern const char kPostQuantumCECPQ2Name[];
 extern const char kPostQuantumCECPQ2Description[];
 
+extern const char kMacCoreLocationImplementationName[];
+extern const char kMacCoreLocationImplementationDescription[];
+
 extern const char kWinrtGeolocationImplementationName[];
 extern const char kWinrtGeolocationImplementationDescription[];