Network performance related histograms.
Network performance related histograms.

Added a histogram "Network.Shill.DeviceConnectionStatus" for tracking the
connection status of the device. A sample is emitted once every 3
minutes.

Added a histogram "Network.Shill.Wifi.NetworkProblemDetected" for tracking
the connection problem encountered by TrafficMonitor after the wifi
connection is established. This event is reported whenever a network
problem is encountered while connected to a  wifi network.

Added a histogram "NetworkShill.WiFi.UserInitiatedConnectionFailureReason"
for tracking the reasons for failed wifi connection attempts that are
manually initiated by the user. This event is reported everytime
user-initiated wifi connection attempts failed.

BUG=chromium:374274, chromium:392965, chromium:392990
TEST=Start chrome, and browse to chrome://histograms to verify the
histograms mentioned above exist.
NOTRY=true

Review URL: https://codereview.chromium.org/429353002

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@287826 0039d316-1c4b-4281-b951-d872f2087c98

Chilledheart/chromium,Chilledheart/chromium,markYoungH/chromium.src,Fireblend/chromium-crosswalk,dushu1203/chromium.src,dednal/chromium.src,crosswalk-project/chromium-crosswalk-efl,littlstar/chromium.src,Chilledheart/chromium,hgl888/chromium-crosswalk,dushu1203/chromium.src,ondra-novak/chromium.src,Just-D/chromium-1,chuan9/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Jonekee/chromium.src,littlstar/chromium.src,crosswalk-project/chromium-crosswalk-efl,hgl888/chromium-crosswalk-efl,mohamed--abdel-maksoud/chromium.src,jaruba/chromium.src,ltilve/chromium,chuan9/chromium-crosswalk,M4sse/chromium.src,Pluto-tv/chromium-crosswalk,fujunwei/chromium-crosswalk,Fireblend/chromium-crosswalk,M4sse/chromium.src,ondra-novak/chromium.src,Pluto-tv/chromium-crosswalk,Just-D/chromium-1,Pluto-tv/chromium-crosswalk,jaruba/chromium.src,Just-D/chromium-1,PeterWangIntel/chromium-crosswalk,ltilve/chromium,bright-sparks/chromium-spacewalk,hgl888/chromium-crosswalk-efl,M4sse/chromium.src,hgl888/chromium-crosswalk,chuan9/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,Just-D/chromium-1,Pluto-tv/chromium-crosswalk,M4sse/chromium.src,ltilve/chromium,dednal/chromium.src,TheTypoMaster/chromium-crosswalk,Just-D/chromium-1,ondra-novak/chromium.src,mohamed--abdel-maksoud/chromium.src,mohamed--abdel-maksoud/chromium.src,Just-D/chromium-1,PeterWangIntel/chromium-crosswalk,Fireblend/chromium-crosswalk,crosswalk-project/chromium-crosswalk-efl,chuan9/chromium-crosswalk,markYoungH/chromium.src,krieger-od/nwjs_chromium.src,chuan9/chromium-crosswalk,fujunwei/chromium-crosswalk,markYoungH/chromium.src,crosswalk-project/chromium-crosswalk-efl,jaruba/chromium.src,dednal/chromium.src,markYoungH/chromium.src,krieger-od/nwjs_chromium.src,ltilve/chromium,axinging/chromium-crosswalk,mohamed--abdel-maksoud/chromium.src,TheTypoMaster/chromium-crosswalk,hgl888/chromium-crosswalk,M4sse/chromium.src,fujunwei/chromium-crosswalk,Fireblend/chromium-crosswalk,hgl888/chromium-crosswalk-efl,bright-sparks/chromium-spacewalk,axinging/chromium-crosswalk,chuan9/chromium-crosswalk,jaruba/chromium.src,mohamed--abdel-maksoud/chromium.src,TheTypoMaster/chromium-crosswalk,hgl888/chromium-crosswalk,jaruba/chromium.src,Jonekee/chromium.src,littlstar/chromium.src,Just-D/chromium-1,crosswalk-project/chromium-crosswalk-efl,Fireblend/chromium-crosswalk,hgl888/chromium-crosswalk,mohamed--abdel-maksoud/chromium.src,Chilledheart/chromium,ltilve/chromium,dushu1203/chromium.src,Fireblend/chromium-crosswalk,crosswalk-project/chromium-crosswalk-efl,dushu1203/chromium.src,hgl888/chromium-crosswalk-efl,markYoungH/chromium.src,markYoungH/chromium.src,hgl888/chromium-crosswalk,crosswalk-project/chromium-crosswalk-efl,krieger-od/nwjs_chromium.src,dushu1203/chromium.src,ondra-novak/chromium.src,hgl888/chromium-crosswalk-efl,bright-sparks/chromium-spacewalk,crosswalk-project/chromium-crosswalk-efl,dednal/chromium.src,hgl888/chromium-crosswalk-efl,Pluto-tv/chromium-crosswalk,fujunwei/chromium-crosswalk,Jonekee/chromium.src,bright-sparks/chromium-spacewalk,Chilledheart/chromium,ltilve/chromium,PeterWangIntel/chromium-crosswalk,ondra-novak/chromium.src,Pluto-tv/chromium-crosswalk,fujunwei/chromium-crosswalk,ltilve/chromium,krieger-od/nwjs_chromium.src,ondra-novak/chromium.src,axinging/chromium-crosswalk,Fireblend/chromium-crosswalk,Chilledheart/chromium,dushu1203/chromium.src,crosswalk-project/chromium-crosswalk-efl,jaruba/chromium.src,Jonekee/chromium.src,M4sse/chromium.src,axinging/chromium-crosswalk,M4sse/chromium.src,littlstar/chromium.src,mohamed--abdel-maksoud/chromium.src,dushu1203/chromium.src,dednal/chromium.src,M4sse/chromium.src,bright-sparks/chromium-spacewalk,Chilledheart/chromium,ltilve/chromium,dednal/chromium.src,Jonekee/chromium.src,ondra-novak/chromium.src,markYoungH/chromium.src,fujunwei/chromium-crosswalk,hgl888/chromium-crosswalk,dednal/chromium.src,dednal/chromium.src,bright-sparks/chromium-spacewalk,markYoungH/chromium.src,dushu1203/chromium.src,krieger-od/nwjs_chromium.src,Jonekee/chromium.src,dednal/chromium.src,axinging/chromium-crosswalk,axinging/chromium-crosswalk,Jonekee/chromium.src,Jonekee/chromium.src,markYoungH/chromium.src,axinging/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,M4sse/chromium.src,fujunwei/chromium-crosswalk,chuan9/chromium-crosswalk,krieger-od/nwjs_chromium.src,TheTypoMaster/chromium-crosswalk,axinging/chromium-crosswalk,Chilledheart/chromium,PeterWangIntel/chromium-crosswalk,chuan9/chromium-crosswalk,krieger-od/nwjs_chromium.src,jaruba/chromium.src,TheTypoMaster/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,markYoungH/chromium.src,mohamed--abdel-maksoud/chromium.src,jaruba/chromium.src,hgl888/chromium-crosswalk-efl,bright-sparks/chromium-spacewalk,bright-sparks/chromium-spacewalk,mohamed--abdel-maksoud/chromium.src,dednal/chromium.src,PeterWangIntel/chromium-crosswalk,M4sse/chromium.src,chuan9/chromium-crosswalk,Pluto-tv/chromium-crosswalk,M4sse/chromium.src,Chilledheart/chromium,hgl888/chromium-crosswalk-efl,littlstar/chromium.src,mohamed--abdel-maksoud/chromium.src,dushu1203/chromium.src,bright-sparks/chromium-spacewalk,ondra-novak/chromium.src,axinging/chromium-crosswalk,fujunwei/chromium-crosswalk,dushu1203/chromium.src,Jonekee/chromium.src,ltilve/chromium,axinging/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,ondra-novak/chromium.src,hgl888/chromium-crosswalk-efl,hgl888/chromium-crosswalk,axinging/chromium-crosswalk,Fireblend/chromium-crosswalk,fujunwei/chromium-crosswalk,jaruba/chromium.src,markYoungH/chromium.src,dednal/chromium.src,krieger-od/nwjs_chromium.src,PeterWangIntel/chromium-crosswalk,krieger-od/nwjs_chromium.src,TheTypoMaster/chromium-crosswalk,littlstar/chromium.src,TheTypoMaster/chromium-crosswalk,krieger-od/nwjs_chromium.src,littlstar/chromium.src,Just-D/chromium-1,Jonekee/chromium.src,littlstar/chromium.src,krieger-od/nwjs_chromium.src,jaruba/chromium.src,jaruba/chromium.src,Jonekee/chromium.src,Fireblend/chromium-crosswalk,mohamed--abdel-maksoud/chromium.src,hgl888/chromium-crosswalk,hgl888/chromium-crosswalk-efl,Just-D/chromium-1,dushu1203/chromium.src,Pluto-tv/chromium-crosswalk