Android: Change camera fps range selection

This CL changes the logic in
CameraEnumerationAndroid.getClosestSupportedFramerateRange() to prefer
fps ranges with a low lower bound so the camera can adjust for
brightness conditions.

To test the functionality of the fps range selection, JUnit tests are
added. This required a new target in api_tests.gyp. JUnit tests are
preferable over instrumentation tests
(libjingle_peerconnection_android_unittest) because they are faster and
simpler.

R=kjellander@webrtc.org, sakal@webrtc.org

Review URL: https://codereview.webrtc.org/2013413002 .

Cr-Original-Commit-Position: refs/heads/master@{#12964}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: b4ddb5c3d3706b1c02437f6a538576f3552ab908
4 files changed