Calculate reviewer update lists when reviewers or cc changes.
Calculate reviewer update lists when reviewers or cc changes.

Review URL: https://codereview.appspot.com/9859044/

Koulio/rietveld,gco/rietveld,supriyantomaftuh/rietveld,berkus/rietveld,dushmis/rietveld,foolonhill/rietveld,salomon1184/rietveld,dushmis/rietveld,rietveld-codereview/rietveld,rietveld-codereview/rietveld,fuzan/rietveld,DeanHere/rietveld,salomon1184/rietveld,gco/rietveld,gavioto/rietveld,v3ss0n/rietveld,gavioto/rietveld,dushmis/rietveld,supriyantomaftuh/rietveld,salomon1184/rietveld,ericmckean/rietveld,openlabs/cr.openlabs.co.in,aungzanbaw/rietveld,draem0507/rietveld,Koulio/rietveld,arg0/rietveld,openlabs/cr.openlabs.co.in,robfig/rietveld,google-code-export/rietveld,sajingeo/rietveld,v3ss0n/rietveld,Koulio/rietveld,supriyantomaftuh/rietveld,foolonhill/rietveld,arg0/rietveld,xtypebee/rietveld,berkus/rietveld,aungzanbaw/rietveld,xtypebee/rietveld,ericmckean/rietveld,fuzan/rietveld,xtypebee/rietveld,robfig/rietveld,gco/rietveld,aungzanbaw/rietveld,google-code-export/rietveld,andyzsf/rietveld,v3ss0n/rietveld,fuzan/rietveld,gavioto/rietveld,arg0/rietveld,google-code-export/rietveld,sajingeo/rietveld,sajingeo/rietveld,foolonhill/rietveld,rietveld-codereview/rietveld,ericmckean/rietveld,draem0507/rietveld,berkus/rietveld,andyzsf/rietveld,robfig/rietveld,DeanHere/rietveld,DeanHere/rietveld,andyzsf/rietveld,rietveld-codereview/rietveld,openlabs/cr.openlabs.co.in,draem0507/rietveld