Revalidation header blacklisting should be case-insensitive.

Headers like 'content-type' should be ignored for 304 responses, even if
they are delivered as 'Content-Type', or 'CoNtEnT-TyPe', etc.

BUG=246875

Review URL: https://chromiumcodereview.appspot.com/23591029

git-svn-id: svn://svn.chromium.org/blink/trunk@157358 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Revert "Allow configuring CPU profiler sampling interval"

This reverts commit 4933abfbd2cdc88443cd0c57b8a90dd27ce48ec2.

BUG=284998

Review URL: https://chromiumcodereview.appspot.com/23818003

git-svn-id: svn://svn.chromium.org/blink/trunk@157359 bbb929c8-8fbe-4397-9dbb-9b2b20218538