[Android Q&A, Help & Troubleshooting] rumburake:
It's Google+.

Call me crazy but I saw it too and got a bit worried.

I have recently flashed my Nexus 4. I didn't even run Google+ once since.

I was debugging my app in Eclipse when suddenly I see thousands of messages in LogCat (see below).

Later I did actually start Google+ and I got the introductory screens that confirms I never ran it before! Including "do you want contact sync" etc.

I have no face-unlock screen either.

So either the phone was capturing my face or was it trying to face-match all my contacts with their database without asking first... what gives??

I saved the full logs but they look just like the sample below. Anyone interested let me know.

I/ActivityManager( 588): Start proc com.google.android.apps.plus for broadcast com.google.android.apps.plus/.service.PackagesMediaMonitor: pid=25977 uid=10069 gids={50069, 3003, 3002, 1028, 1015}
D/native (25977): region_flow_computation.cc:680 Processing frame 680
D/native (25977): region_flow_computation.cc:1653 Features already present, (tracked 8 times)
D/native (25977): region_flow_computation.cc:2612 Has sufficient features: 71
D/native (25977): motion_estimation.cc:3898 Unstable homography found. Registration (actual, threshold): 2.71539 0.1 Inlier coverage (actual, threshold): 0.110453 0.25
D/native (25977): region_flow_computation.cc:680 Processing frame 681
D/native (25977): region_flow_computation.cc:1653 Features already present, (tracked 9 times)
D/native (25977): region_flow_computation.cc:2612 Has sufficient features: 74
D/native (25977): motion_estimation.cc:3898 Unstable homography found. Registration (actual, threshold): 2.70268 0.1 Inlier coverage (actual, threshold): 0.186833 0.25
D/native (25977): region_flow_computation.cc:680 Processing frame 682

[ ......... 1500 more messages ............ ]

D/native (25977): motion_estimation.cc:4201 Homography estimation failed, less than 9 features usable for estimation.
D/native (25977): region_flow_computation.cc:680 Processing frame 1072
D/native (25977): region_flow_computation.cc:1653 Features already present, (tracked 10 times)
D/native (25977): region_flow_computation.cc:2612 Has sufficient features: 61
D/native (25977): region_flow_computation.cc:680 Processing frame 1073
D/native (25977): region_flow_computation.cc:1653 Features already present, (tracked 11 times)
D/native (25977): region_flow_computation.cc:2612 Has sufficient features: 66
V/async_facetracker(25977): detection thread ended
D/dalvikvm(25977): GC_CONCURRENT freed 11036K, 33% free 30521K/45280K, paused 3ms+38ms, total 112ms
D/dalvikvm(25977): GC_CONCURRENT freed 8579K, 36% free 29068K/45280K, paused 3ms+9ms, total 83ms
D/dalvikvm(25977): GC_CONCURRENT freed 6781K, 37% free 28960K/45280K, paused 6ms+11ms, total 85ms
D/dalvikvm(25977): WAIT_FOR_CONCURRENT_GC blocked 62ms
D/dalvikvm(25977): GC_CONCURRENT freed 6609K, 36% free 29000K/45280K, paused 6ms+23ms, total 105ms
D/dalvikvm(25977): WAIT_FOR_CONCURRENT_GC blocked 68ms
D/dalvikvm(25977): WAIT_FOR_CONCURRENT_GC blocked 69ms
D/dalvikvm(25977): GC_CONCURRENT freed 6164K, 34% free 29436K/44140K, paused 7ms+11ms, total 76ms
D/dalvikvm(25977): GC_CONCURRENT freed 6800K, 34% free 29361K/44140K, paused 2ms+10ms, total 60ms
D/dalvikvm(25977): GC_CONCURRENT freed 6984K, 35% free 29099K/44140K, paused 3ms+9ms, total 59ms
D/dalvikvm(25977): GC_CONCURRENT freed 6666K, 35% free 29079K/44140K, paused 2ms+8ms, total 49ms
D/dalvikvm(25977): GC_CONCURRENT freed 6677K, 35% free 29071K/44140K, paused 3ms+9ms, total 73ms
D/dalvikvm(25977): Trying to load lib /data/app-lib/com.google.android.apps.plus-2/libwebp_android.so 0x42580b00
D/dalvikvm(25977): Added shared lib /data/app-lib/com.google.android.apps.plus-2/libwebp_android.so 0x42580b00
D/dalvikvm(25977): GC_FOR_ALLOC freed 1728K, 33% free 29979K/44140K, paused 33ms, total 33ms
I/dalvikvm-heap(25977): Grow heap (frag case) to 31.282MB for 2073616-byte allocation
D/dalvikvm(25977): GC_FOR_ALLOC freed 2K, 31% free 32001K/46168K, paused 32ms, total 32ms
D/OpenGLRenderer(25977): Enabling debug mode 0