Add UMA histogram to track the various sources that request the feedback app

chrome/browser/feedback/show_feedback_page.cc

Index: chrome/browser/feedback/show_feedback_page.cc
diff --git a/chrome/browser/feedback/show_feedback_page.cc b/chrome/browser/feedback/show_feedback_page.cc
index d3e0cd8ee5c7fb96be68a586fa557a2df2d4b0eb..d3091ba715bb504e35c2aabfd09a07a65998b974 100644
--- a/chrome/browser/feedback/show_feedback_page.cc
+++ b/chrome/browser/feedback/show_feedback_page.cc
@@ -4,10 +4,12 @@
 
 #include <string>
 
+#include "base/metrics/histogram_macros.h"
 #include "chrome/browser/extensions/api/feedback_private/feedback_private_api.h"
 #include "chrome/browser/feedback/feedback_dialog_utils.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
+#include "chrome/browser/ui/chrome_pages.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "chrome/browser/ui/webui/md_feedback/md_feedback_dialog_controller.h"
 #include "chrome/common/chrome_switches.h"
@@ -15,6 +17,7 @@
 namespace chrome {
 
 void ShowFeedbackPage(Browser* browser,
+                      FeedbackSource source,
                       const std::string& description_template,
                       const std::string& category_tag) {
   GURL page_url;
@@ -29,6 +32,10 @@ void ShowFeedbackPage(Browser* browser,
     return;
   }
 
+  // Record an UMA histogram to know the most frequent feedback request source.
+  UMA_HISTOGRAM_ENUMERATION("Feedback.RequestSource", source,
+                            kFeedbackSourceCount);
+
   if (::switches::MdFeedbackEnabled()) {
     MdFeedbackDialogController::GetInstance()->Show(profile);
     return;