[PageInfo] add optnone to work around a clang bug

Chrome OS can't roll Chrome due to crbug.com/1030099. Given our
proximity to the branch, a source-level workaround, if simple, seems
prudent. Adding `optnone` here appears to be that workaround.

Bug: 1030099
Change-Id: I9c5ddbff3715e44f26f628b5540b1455ab56ba79
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1952383Reviewed-by: Patti <patricialor@chromium.org>
Commit-Queue: George Burgess <gbiv@chromium.org>
Cr-Commit-Position: refs/heads/master@{#721845}

chrome/browser/ui/page_info/page_info.cc

@@ -657,7 +657,10 @@ void PageInfo::OnWhitelistPasswordReuseButtonPressed(
 #endif
 }
 
-void PageInfo::ComputeUIInputs(
+// TODO(crbug.com/1030099): ComputeUIInputs causes Chrome OS' compiler to hang
+// during an optimization pass; optnone appears to fix that. Remove this once
+// that's fixed.
+__attribute__((optnone)) void PageInfo::ComputeUIInputs(
     const GURL& url,
     security_state::SecurityLevel security_level,
     const security_state::VisibleSecurityState& visible_security_state) {