GitLab

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: svn://svn.chromium.org/chrome/trunk/src@287826 0039d316-1c4b-4281-b951-d872f2087c98