Simplify the text in the external protocol confirmation dialog.

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 d4c791ab4cd110a02e3823a2d13ce695c29618eb..c9dcb64280fa13c33631320972b587bf92b66b2a 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -4829,6 +4829,17 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <summary>Maximal amount of memory allocated by decoder.</summary>
 </histogram>
 
+<histogram name="BrowserDialogs.ExternalProtocol.RememberCheckbox"
+    enum="BooleanChecked">
+  <owner>dominickn@chromium.org</owner>
+  <summary>
+    Whether or not the user checked the option in the external protocol dialog
+    to remember their choice of opening or not opening the specified app.
+    Recorded each time the user interacts with the External Protocol Dialog
+    (either accepting or cancelling/dismissing).
+  </summary>
+</histogram>
+
 <histogram name="BrowserRenderProcessHost.ChildCrashes" enum="RendererType">
   <owner>wfh@chromium.org</owner>
   <summary>Count of renderer process crashes grouped by type.</summary>
@@ -72902,6 +72913,11 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="1" label="Changed"/>
 </enum>
 
+<enum name="BooleanChecked" type="int">
+  <int value="0" label="Not checked"/>
+  <int value="1" label="Checked"/>
+</enum>
+
 <enum name="BooleanCloseTimeout" type="int">
   <int value="0" label="Closed normally"/>
   <int value="1" label="Timed out"/>