Metrics logging for user engagement of the Reload and Feedback buttons

ios/chrome/browser/ui/sad_tab/sad_tab_view.mm

Index: ios/chrome/browser/ui/sad_tab/sad_tab_view.mm
diff --git a/ios/chrome/browser/ui/sad_tab/sad_tab_view.mm b/ios/chrome/browser/ui/sad_tab/sad_tab_view.mm
index ac2fc8a36cb6f9e02791d2df7247f4c3abae99db..c3c18ce555bd5a6d8de28b1d0964d620ef840b57 100644
--- a/ios/chrome/browser/ui/sad_tab/sad_tab_view.mm
+++ b/ios/chrome/browser/ui/sad_tab/sad_tab_view.mm
@@ -4,6 +4,7 @@
 
 #import "ios/chrome/browser/ui/sad_tab/sad_tab_view.h"
 
+#include "base/metrics/histogram_macros.h"
 #include "base/strings/sys_string_conversions.h"
 #include "components/grit/components_scaled_resources.h"
 #include "components/strings/grit/components_strings.h"
@@ -117,6 +118,15 @@ NSString* const kMessageLabelBulletRTLFormat = @"\u202E%@\u202C";
 
 @end
 
+// An enum for reporting interaction events to a UMA histogram. This
+// enumeration mimics that at sad_tab.cc
+typedef NS_ENUM(NSInteger, SadTabViewEvent) {

[PL, 2017/05/09 22:38:23]

This enumeration copies one reporting this metric for Desktop in sad_tab.cc.
I'd like to make both implementations use the same enumeration if possible.
If you agree, what would be the way to do this?:
a. File a bug for Desktop team to make their enum (and keys) public. Then adopt?
b. Place our own C++ enum somewhere accessible to both platforms and file a bug
for Desktop to adopt? If so, where?
c. Something else.

Thanks!

[Eugene But (OOO till 7-30), 2017/05/09 22:45:58]

I think it is C :). We should find a common place for this enum (perhaps in
components layer) and make changes for Desktop as well. isherman@ may help you
with finding a good place for the enum.

[PL, 2017/05/09 22:57:20]

Thanks! Reached out to isherman@ and sdy@ for discussion.

+  SadTabViewEventDisplayed = 0,
+  SadTabViewEventButtonClicked,
+  SadTabViewEventHelpLinkClicked,
+  SadTabViewEventMaxSadTabEvent,
+};
+
 #pragma mark - SadTabView
 
 @implementation SadTabView
@@ -523,9 +533,15 @@ NSString* const kMessageLabelBulletRTLFormat = @"\u202E%@\u202C";
 - (void)handleActionButtonTapped:(id)sender {
   switch (self.mode) {
     case SadTabViewMode::RELOAD:
+      UMA_HISTOGRAM_ENUMERATION("Tabs.SadTab.Reload.Event",
+                                SadTabViewEventButtonClicked,
+                                SadTabViewEventMaxSadTabEvent);
       self.navigationManager->Reload(web::ReloadType::NORMAL, true);
       break;
     case SadTabViewMode::FEEDBACK: {
+      UMA_HISTOGRAM_ENUMERATION("Tabs.SadTab.Feedback.Event",
+                                SadTabViewEventButtonClicked,
+                                SadTabViewEventMaxSadTabEvent);
       GenericChromeCommand* command =
           [[GenericChromeCommand alloc] initWithTag:IDC_REPORT_AN_ISSUE];
       [self chromeExecuteCommand:command];