TimelinePanel: fix for white horizontal bar in records view after initial show.

parent of recordsView had x-scrollbar and affected the size of child views.

Drive by fix: disable y-scrollbar of Memory counters sidebar view.

BUG=326121
R=pfeldman@chromium.org

Review URL: https://codereview.chromium.org/143323002

git-svn-id: svn://svn.chromium.org/blink/trunk@165403 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Add WorkerGlobalScope* param to WorkerReportingProxy::workerGlobalScopeStarted

To make ServiceWorker wiring slightly easier.
(This method is currently used only by ServiceWorker)

BUG=313530

Review URL: https://codereview.chromium.org/137633004

git-svn-id: svn://svn.chromium.org/blink/trunk@165404 bbb929c8-8fbe-4397-9dbb-9b2b20218538