I use this script to copy the selected text in a Safari page.
set textSelected to my safeCopy("Safari")
#=====
on safeCopy(theApp)
local tt
(*
Fill the clipboard with a fake string *)
set tt to "All The Things You Could Be By Now If Sigmund Freud’s Wife Was Your Mother, © Charles Mingus"
set the clipboard to tt
activate application theApp
delay 0.1 # required with Yosemite
tell application "System Events" to tell process theApp
keystroke "c" using {command down}
end tell
(*
Loop waiting the achievement of the Copy task. *)
repeat 10 times
try
delay 0.2
if (the clipboard as text) is not tt then exit repeat
end try
end repeat
end safeCopy
#=====
Check that it works for you then, if it does (as I guess), replace "Safari" by the name of the Google Chrome application.