Add a histogram "Download.FeedbackDialogEnabled"

This adds a new UMA histogram, "Download.FeedbackDialogEnabled." The histogram tells us how the user responded to the opt-in reporting dialog (enabled = true, disabled = false).

BUG=312533

Review URL: https://codereview.chromium.org/163433012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251488 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/ui/views/download/download_feedback_dialog_view.cc

@@ -4,6 +4,7 @@
 
 #include "chrome/browser/ui/views/download/download_feedback_dialog_view.h"
 
+#include "base/metrics/histogram.h"
 #include "base/prefs/pref_service.h"
 #include "base/supports_user_data.h"
 #include "chrome/browser/profiles/profile.h"
@@ -92,6 +93,8 @@ bool DownloadFeedbackDialogView::OnButtonClicked(bool accepted) {
   DCHECK(data);
   data->set_currently_shown(false);
 
+  UMA_HISTOGRAM_BOOLEAN("Download.FeedbackDialogEnabled", accepted);
+
   callback_.Run(accepted);
   return true;
 }

tools/metrics/histograms/histograms.xml

@@ -3203,6 +3203,13 @@ other types of suffix sets.
   </summary>
 </histogram>
 
+<histogram name="Download.FeedbackDialogEnabled" enum="BooleanEnabled">
+  <summary>
+    Whether the user enables dangerous download feedback reporting after viewing
+    the opt-in dialog.
+  </summary>
+</histogram>
+
 <histogram name="Download.FilePickerResult" enum="DownloadFilePickerResult">
   <summary>
     How the user interacts with the file chooser when doing a &quot;Save