Omnibox: Add UMA Histogram to Dashboard

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 56bae39d1dc22d7bd876aed88d1b05e7a0845f9c..130c23def9531c5a60bfc3253b76c2675f0fbcf8 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -2403,6 +2403,13 @@ other types of suffix sets.
   <summary>The time that a Wi-fi scan takes.</summary>
 </histogram>
 
+<histogram name="Omnibox.EnteredKeywordMode" enum="OmniboxEnteredKeywordMode">
+  <summary>
+    The number of times users enter keyword hint mode &quot;Search ___
+    for:&quot; and how.
+  </summary>
+</histogram>
+
 <histogram name="PlatformFile.UnknownCreateFileErrors" units="code">
   <summary>
     Errors returned by CreateFile on windows that PlatformFileError doesn't yet
@@ -4667,6 +4674,12 @@ other types of suffix sets.
   <int value="8" label="subresource and used"/>
 </enum>
 
+<enum name="OmniboxEnteredKeywordMode" type="int">
+  <int value="0" label="via tab"/>
+  <int value="1" label="via space at end"/>
+  <int value="2" label="via space in middle"/>
+</enum>
+
 <enum name="OSAgnosticErrno" type="int">
   <summary>Errno values with the same meanings on Mac/Win/Linux.</summary>
   <int value="0" label="0">No error</int>