mLastTickInNanoSeconds is the renderStart

because:
this.mLastTickInNanoSeconds = renderEnd - renderInterval;
renderInterval = renderEnd - renderStart
so:
this.mLastTickInNanoSeconds = renderEnd - ( renderEnd - renderStart );
so:
this.mLastTickInNanoSeconds = renderStart ;

so:
no need nanoTime() twice
Merge pull request #7782 from liang8305/v3

mLastTickInNanoSeconds is the renderStart