Revert "Move ev_root_ca_metadata to read-only data segment"

This reverts commit 60cd9d98 now that we
don't need to work around the VC++ bug.

The array was subsequently changed from char[] to StringPiece so it's
not really a revert but an adding back of const to where it used to be,
with somewhat different semantics.

Bug: 934323
Change-Id: I821025578923e91218b8827d1d6cdd3553c252b2
Reviewed-on: https://chromium-review.googlesource.com/c/1484415
Auto-Submit: Bruce Dawson <brucedawson@chromium.org>
Commit-Queue: Steven Valdez <svaldez@chromium.org>
Reviewed-by: Steven Valdez <svaldez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#635624}

net/cert/ev_root_ca_metadata.cc

@@ -43,7 +43,7 @@ struct EVMetadata {
   SHA256HashValue fingerprint;
 
   // The EV policy OIDs of the root CA.
-  base::StringPiece policy_oids[kMaxOIDsPerCA];
+  const base::StringPiece policy_oids[kMaxOIDsPerCA];
 };
 
 // These certificates may be found in net/data/ssl/ev_roots.