[DevTools] Refactor screencast view heirarchy.

BUG=311249

Review URL: https://codereview.chromium.org/116353002

git-svn-id: svn://svn.chromium.org/blink/trunk@164015 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: Show the last valid value for GPU memory counter.

Currently the graph drops to zero at the chart righthand side.

R=yurys@chromium.org

Review URL: https://codereview.chromium.org/117243002

git-svn-id: svn://svn.chromium.org/blink/trunk@164016 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Delete Profiler.resetProfiles event from the protocol

The event was sent on navigation that changed render process. Since collected profiles are not stored on the back-end anymore we can leave them on the front-end after navigation.

Front-end initiated profile will continue recording after changing render process. All console initiated profiles will stop. Ids of Profiler.consolerProfileStarted events will remain unique after navigation.

BUG=327298
R=pfeldman@chromium.org

Review URL: https://codereview.chromium.org/106093009

git-svn-id: svn://svn.chromium.org/blink/trunk@164017 bbb929c8-8fbe-4397-9dbb-9b2b20218538