Add histograms for shill network metrics

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index 65d16025996f576bbbcd682f0b53093959a19207..832c43b428b3f1829989a9c3d6597a43e82595a8 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -15198,6 +15198,9 @@ Therefore, the affected-histogram name has to have at least one dot in it.
 
 <histogram name="Network.Shill.Cellular.DHCPOptionFailureDetected"
     enum="NetworkDHCPOptionFailure">
+  <obsolete>
+    Deprecated 5/2014, and replaced by Network.Shill.DHCPOptionFailureDetected.
+  </obsolete>
   <owner>quiche@chromium.org</owner>
   <summary>
     Chrome OS network metric that tracks the number of DHCP option failures
@@ -15359,8 +15362,22 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="Network.Shill.DHCPOptionFailureDetected"
+    enum="NetworkTechnology">
+  <owner>zqiu@chromium.org</owner>
+  <summary>
+    Chrome OS network metric that tracks the number of DHCP option failures
+    encountered by Shill for each network technology.  This indicates that Shill
+    is using minimal DHCP options due to suspected MTU issues on the return path
+    from the DHCP server back to the client.
+  </summary>
+</histogram>
+
 <histogram name="Network.Shill.Ethernet.DHCPOptionFailureDetected"
     enum="NetworkDHCPOptionFailure">
+  <obsolete>
+    Deprecated 5/2014, and replaced by Network.Shill.DHCPOptionFailureDetected.
+  </obsolete>
   <owner>quiche@chromium.org</owner>
   <summary>
     Chrome OS network metric that tracks the number of DHCP option failures
@@ -15574,6 +15591,13 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="Network.Shill.UserInitiatedEvents" enum="UserInitiatedEvent">
+  <owner>zqiu@chromium.org</owner>
+  <summary>
+    Chrome OS network metric that tracks the number of user-initiated events.
+  </summary>
+</histogram>
+
 <histogram name="Network.Shill.Vpn.Driver" enum="VPNDriver">
   <owner>quiche@chromium.org</owner>
   <summary>
@@ -15695,6 +15719,9 @@ Therefore, the affected-histogram name has to have at least one dot in it.
 
 <histogram name="Network.Shill.Wifi.DHCPOptionFailureDetected"
     enum="NetworkDHCPOptionFailure">
+  <obsolete>
+    Deprecated 5/2014, and replaced by Network.Shill.DHCPOptionFailureDetected.
+  </obsolete>
   <owner>quiche@chromium.org</owner>
   <summary>
     Chrome OS network metric that tracks the number of DHCP option failures
@@ -15948,8 +15975,29 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="Network.Shill.WiFi.TransmitBitrateMbps" units="Mbps">
+  <owner>zqiu@chromium.org</owner>
+  <summary>
+    Chrome OS network performance metric that tracks the transmit bitrate in
+    Mbps for the wifi device when it is connected to a network. The bitrate is
+    reported once every minute after the wifi connection is established.
+  </summary>
+</histogram>
+
+<histogram name="Network.Shill.WiFi.UserInitiatedConnectionResult"
+    enum="ConnectionResult">
+  <owner>zqiu@chromium.org</owner>
+  <summary>
+    Chrome OS network performance metric that tracks the result of
+    user-initiated wifi connection attempts.
+  </summary>
+</histogram>
+
 <histogram name="Network.Shill.WiMax.DHCPOptionFailureDetected"
     enum="NetworkDHCPOptionFailure">
+  <obsolete>
+    Deprecated 5/2014, and replaced by Network.Shill.DHCPOptionFailureDetected.
+  </obsolete>
   <owner>quiche@chromium.org</owner>
   <summary>
     Chrome OS network metric that tracks the number of DHCP option failures
@@ -32128,6 +32176,12 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   <int value="1" label="GPU compositor"/>
 </enum>
 
+<enum name="ConnectionResult" type="int">
+  <int value="0" label="Success"/>
+  <int value="1" label="Failure"/>
+  <int value="2" label="Aborted"/>
+</enum>
+
 <enum name="ConnectionType" type="int">
   <summary>
     Connection type as defined in net/base/connection_type_histograms.h
@@ -38545,6 +38599,16 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   <int value="14" label="HTTP_GET_FAILED"/>
 </enum>
 
+<enum name="NetworkTechnology" type="int">
+  <int value="0" label="Cellular"/>
+  <int value="1" label="Ethernet"/>
+  <int value="2" label="Ethernet EAP"/>
+  <int value="3" label="WiFi"/>
+  <int value="4" label="WiMax"/>
+  <int value="5" label="VPN"/>
+  <int value="6" label="Unknown"/>
+</enum>
+
 <enum name="NewTabPageActionAndroid" type="int">
   <int value="0" label="Searched using the omnibox"/>
   <int value="1" label="Navigated to Google search homepage using the omnibox"/>
@@ -42868,6 +42932,10 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   <int value="10" label="kFileSystemScheme"/>
 </enum>
 
+<enum name="UserInitiatedEvent" type="int">
+  <int value="0" label="WiFi Scan"/>
+</enum>
+
 <enum name="UserSelectableSyncType" type="int">
   <int value="0" label="Bookmarks"/>
   <int value="1" label="Preferences"/>