TimelineFlameChart: FlameChart in Timeline has to have the standard Timeline colors.

ColorGenerator ownership was fixed. Now it is a property of DataProvider.
Separate instance of the color generator for TimelineFlameChart was supported.
Custom color assignment procedure setColorPairForId was added to the ColorGenerator API
fillStyles from TimelineFrameOverview was pushed into the color generator for TimelineFlameChart.

BUG=316167
R=pfeldman@chromium.org

Review URL: https://codereview.chromium.org/156113004

git-svn-id: svn://svn.chromium.org/blink/trunk@166841 bbb929c8-8fbe-4397-9dbb-9b2b20218538