Add UMA and Rappor metrics to capture URLs passed in at startup.

tools/metrics/rappor/rappor.xml

Index: tools/metrics/rappor/rappor.xml
diff --git a/tools/metrics/rappor/rappor.xml b/tools/metrics/rappor/rappor.xml
index 0c9da723d43f665146eb84ea08550d9a15e6f085..9a9e53a937f614a68d279a7951821c00e079d851 100644
--- a/tools/metrics/rappor/rappor.xml
+++ b/tools/metrics/rappor/rappor.xml
@@ -31,7 +31,7 @@ components/rappor/rappor_service.cc.
 <rappor-parameters name="ETLD_PLUS_ONE">
   <summary>
     Deprecated parameters for collecting the domain and registry of a URL from
-    UMA opt-in users.
+    UMA opt-in users. Should use UMA_RAPPOR_TYPE instead.
   </summary>
   <parameters num-cohorts="128" bytes="16" hash-functions="2" fake-prob="0.5"
       fake-one-prob="0.5" one-coin-prob="0.75" zero-coin-prob="0.25"
@@ -545,6 +545,16 @@ components/rappor/rappor_service.cc.
   </summary>
 </rappor-metric>
 
+<rappor-metric name="Startup.BrowserLaunchURL" type="UMA_RAPPOR_TYPE">
+  <owner>rkaplow@chromium.org</owner>
+  <summary>
+    The eTLD+1 of a URL that was passed in from the command line when Chrome
+    is invoked. Note that this handles the case of a URL passed to Chrome
+    starting up, or when a running Chrome is given the message to open a new
+    URL.
+  </summary>
+</rappor-metric>
+
 <rappor-metric name="WebComponents.DocumentRegisterElement"
     type="ETLD_PLUS_ONE">
   <owner>kojii@chromium.org</owner>