Update the year in copyright headers from 2016 to 2017, and also rename a
variable in FallbackDesktopCapturerWrapperTest to follow coding style.
BUG=webrtc:7205
Review-Url: https://codereview.webrtc.org/2706193005
Cr-Commit-Position: refs/heads/master@{#16759}
FallbackDesktopCapturerWrapper is a DesktopCapturer implementation, which owns
two DesktopCapturer implementations. If the main DesktopCapturer fails, it uses
the secondary capturer. The logic is now used in ScreenCapturerWinMagnifier, and
it can also be shared in ScreenCapturerWinDirectx to fallback to Gdi capturer on
privilege prompt or login screen.
BUG=684937
Review-Url: https://codereview.webrtc.org/2697453002
Cr-Commit-Position: refs/heads/master@{#16677}
