Gr-tooltip is used for displaying the score explanation. In order to
have gr-tooltip being applied, gr-label component was introduced as a
<span> tag replacement.
Gr-tooltip bug fixes:
- Tooltip arrow now moves sideways if toolip was shown close to left
window side.
- Tooltip positioning was broken anywhere bug in fixed container's child.
- Positioning math updated to use standart getBoundingClientRect instead
of DOM traversal.
Feature: Issue 4101
Change-Id: If62ecff33535b910b311c984993e402c6dc36be7
2603965c12