Create histograms to track time-to-error values for different errors.

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 7b6aba272ebb8407ff7973bc288f66d54e635ae6..0b74480bd5a34ce0f33f90237aae80a1f374a757 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -21155,6 +21155,70 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="Net.RequestTime.ErrAborted">

[Alexei Svitkine (slow), 2015/05/13 16:55:30]

You can use the histogram_suffixes feature to make this more concise - see docs
at the top of the file and examples throughout.

[Randy Smith (Not in Mondays), 2015/05/13 18:29:56]

I didn't find a way to use the same names; it looked from the docs like using
suffices for real always used "_", and using suffix with order=prefix put things
after the first ".", not the second.  So I switched names and used
histogram_suffixes; please let e know if I did something wrong. 

[Alexei Svitkine (slow), 2015/05/13 18:46:17]

You can specify separator="." if you'd like.

+  <owner>rdsmith@chromium.org</owner>
+  <summary>
+    The amount of time between request initiation and request abort, for aborted
+    main frame requests.
+  </summary>
+</histogram>
+
+<histogram name="Net.RequestTime.ErrConnectionReset">
+  <owner>rdsmith@chromium.org</owner>
+  <summary>
+    The amount of time between request initiation and connection reset, for main
+    frame requests which end in connection reset.
+  </summary>
+</histogram>
+
+<histogram name="Net.RequestTime.ErrConnectionTimedOut">
+  <owner>rdsmith@chromium.org</owner>
+  <summary>
+    The amount of time between request initiation and connection timeout, for
+    main frame requests which end in connection reset.
+  </summary>
+</histogram>
+
+<histogram name="Net.RequestTime.ErrInternetDisconnected">
+  <owner>rdsmith@chromium.org</owner>
+  <summary>
+    The amount of time between request initiation and internet disconnected, for
+    main frame requests which end in internet disconnected.
+  </summary>
+</histogram>
+
+<histogram name="Net.RequestTime.ErrNameNotResolved">
+  <owner>rdsmith@chromium.org</owner>
+  <summary>
+    The amount of time between request initiation and the request failing, for
+    main frame requests that fail with Name Not Resolved errors.
+  </summary>
+</histogram>
+
+<histogram name="Net.RequestTime.ErrTimedOut">
+  <owner>rdsmith@chromium.org</owner>
+  <summary>
+    The amount of time between request initiation and request timeout, for timed
+    out main frame requests.
+  </summary>
+</histogram>
+
+<histogram name="Net.RequestTime.MiscError">
+  <owner>rdsmith@chromium.org</owner>
+  <summary>
+    The amount of time between request initiation and error detection, for main
+    frame requests which end in an error not otherwise logged.
+  </summary>
+</histogram>
+
+<histogram name="Net.RequestTime.Success">
+  <owner>rdsmith@chromium.org</owner>
+  <summary>
+    The amount of time between request initiation and reading the last response
+    byte from the network, for successful main frame requests.
+  </summary>
+</histogram>
+
 <histogram name="Net.ResourceLoader.ReadDeferral" units="milliseconds">
   <owner>clamy@chromium.org</owner>
   <summary>