Indexed DB: Disable transaction inactivity timeout in browser tests
To work around wedged renderers stalling the transaction queue, we
impose a timeout. Once a transaction has kicked off, if no new
requests are posted within 60s we assume the renderer is stalled but
not terminated, and abort the transaction. It appears we're hitting
this when browser tests are run under MSAN, Dr. Memory, and so on.
Override the default timeout in browser tests to prevent this.
BUG=505609
R=cmumford@chromium.org
Review URL: https://codereview.chromium.org/
1285303002
Cr-Commit-Position: refs/heads/master@{#343948}