Add UMA metrics to measure the dismissal cause of dialogs.

chrome/browser/ui/javascript_dialogs/javascript_dialog_tab_helper.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/javascript_dialogs/javascript_dialog_tab_helper.h"
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/feature_list.h"
 #include "base/metrics/histogram_macros.h"
@@ skipping 38 matching lines @@
 // That will clear the callback inside of JavaScriptDialog, and start the
 // JavaScriptDialog on its own path of destruction. CloseDialog() then calls
 // ClearDialogInfo() which removes observers.
 //
 // If closing is initiated by the JavaScriptDialog, which is a self-deleting
 // object, then it will make its callback. The callback will have been wrapped
 // within JavaScriptDialogTabHelper::RunJavaScriptDialog() to be a call to
 // JavaScriptDialogTabHelper::OnDialogClosed(), which, after doing the callback,
 // again calls ClearDialogInfo() to remove observers.
 
+enum class JavaScriptDialogTabHelper::DismissalCause {

[Ilya Sherman, 2016/11/29 03:10:35]

Please document that this enum is used to back an UMA histogram, and should
therefore be treated as append-only.

[Avi (use Gerrit), 2016/11/29 16:10:59]

Done.

+  TAB_HELPER_DESTROYED = 0,
+  SUBSEQUENT_DIALOG_SHOWN = 1,
+  HANDLE_DIALOG_CALLED = 2,
+  CANCEL_DIALOGS_CALLED = 3,
+  TAB_HIDDEN = 4,
+  BROWSER_SWITCHED = 5,
+  DIALOG_BUTTON_CLICKED = 6,
+  MAX,
+};
+
 JavaScriptDialogTabHelper::JavaScriptDialogTabHelper(
     content::WebContents* web_contents)
     : content::WebContentsObserver(web_contents) {
 }
 
 JavaScriptDialogTabHelper::~JavaScriptDialogTabHelper() {
-  if (dialog_)
-    CloseDialog(true /*suppress_callback*/, false, base::string16());
+  if (dialog_) {
+    CloseDialog(true /*suppress_callback*/, false, base::string16(),
+                DismissalCause::TAB_HELPER_DESTROYED);
+  }
 }
 
 void JavaScriptDialogTabHelper::SetDialogShownCallbackForTesting(
     base::Closure callback) {
   dialog_shown_ = callback;
 }
 
 void JavaScriptDialogTabHelper::RunJavaScriptDialog(
     content::WebContents* alerting_web_contents,
     const GURL& origin_url,
@@ skipping 47 matching lines @@
           "A window.prompt() dialog generated by this page was suppressed "
           "because this page is not the active tab of the front window. "
           "Please make sure your dialogs are triggered by user interactions "
           "to avoid this situation. "
           "https://www.chromestatus.com/feature/5637107137642496");
       return;
     }
 
     if (dialog_) {
       // There's already a dialog up; clear it out.
-      CloseDialog(false, false, base::string16());
+      CloseDialog(false, false, base::string16(),
+                  DismissalCause::SUBSEQUENT_DIALOG_SHOWN);
     }
 
     base::string16 title =
         AppModalDialogManager()->GetTitle(alerting_web_contents, origin_url);
     dialog_callback_ = callback;
+    message_type_ = message_type;
     dialog_ = JavaScriptDialog::Create(
         parent_web_contents, alerting_web_contents, title, message_type,
         message_text, default_prompt_text,
         base::Bind(&JavaScriptDialogTabHelper::OnDialogClosed,
                    base::Unretained(this), callback));
 
     BrowserList::AddObserver(this);
 
     // Message suppression is something that we don't give the user a checkbox
     // for any more. It was useful back in the day when dialogs were app-modal
@@ skipping 56 matching lines @@
       web_contents, is_reload,
       base::Bind(&SaveUnloadUmaStats, engagement_score, callback));
 }
 
 bool JavaScriptDialogTabHelper::HandleJavaScriptDialog(
     content::WebContents* web_contents,
     bool accept,
     const base::string16* prompt_override) {
   if (dialog_) {
     CloseDialog(false /*suppress_callback*/, accept,
-                prompt_override ? *prompt_override : base::string16());
+                prompt_override ? *prompt_override : base::string16(),
+                DismissalCause::HANDLE_DIALOG_CALLED);
     return true;
   }
 
   // Handle any app-modal dialogs being run by the app-modal dialog system.
   return AppModalDialogManager()->HandleJavaScriptDialog(web_contents, accept,
                                                          prompt_override);
 }
 
 void JavaScriptDialogTabHelper::CancelDialogs(
     content::WebContents* web_contents,
     bool suppress_callbacks,
     bool reset_state) {
   if (dialog_)
-    CloseDialog(suppress_callbacks, false, base::string16());
+    CloseDialog(suppress_callbacks, false, base::string16(),
+                DismissalCause::CANCEL_DIALOGS_CALLED);
 
   // Cancel any app-modal dialogs being run by the app-modal dialog system.
   return AppModalDialogManager()->CancelDialogs(
       web_contents, suppress_callbacks, reset_state);
 }
 
 void JavaScriptDialogTabHelper::WasHidden() {
-  if (dialog_)
-    CloseDialog(false, false, base::string16());
+  if (dialog_) {
+    CloseDialog(false, false, base::string16(), DismissalCause::TAB_HIDDEN);
+  }
 }
 
 void JavaScriptDialogTabHelper::OnBrowserSetLastActive(Browser* browser) {
-  if (dialog_ && !IsWebContentsForemost(web_contents()))
-    CloseDialog(false, false, base::string16());
+  if (dialog_ && !IsWebContentsForemost(web_contents())) {
+    CloseDialog(false, false, base::string16(),
+                DismissalCause::BROWSER_SWITCHED);
+  }
+}
+
+void JavaScriptDialogTabHelper::LogDialogDismissalCause(
+    JavaScriptDialogTabHelper::DismissalCause cause) {
+  switch (message_type_) {
+    case content::JAVASCRIPT_MESSAGE_TYPE_ALERT:
+      UMA_HISTOGRAM_ENUMERATION("JSDialogs.DismissalCause.Alert",
+                                static_cast<int>(cause),
+                                static_cast<int>(DismissalCause::MAX));
+      break;
+    case content::JAVASCRIPT_MESSAGE_TYPE_CONFIRM:
+      UMA_HISTOGRAM_ENUMERATION("JSDialogs.DismissalCause.Confirm",
+                                static_cast<int>(cause),
+                                static_cast<int>(DismissalCause::MAX));
+      break;
+    case content::JAVASCRIPT_MESSAGE_TYPE_PROMPT:
+      UMA_HISTOGRAM_ENUMERATION("JSDialogs.DismissalCause.Prompt",
+                                static_cast<int>(cause),
+                                static_cast<int>(DismissalCause::MAX));
+      break;
+  }
 }
 
 void JavaScriptDialogTabHelper::OnDialogClosed(
     DialogClosedCallback callback,
     bool success,
     const base::string16& user_input) {
+  LogDialogDismissalCause(DismissalCause::DIALOG_BUTTON_CLICKED);
   callback.Run(success, user_input);
 
   ClearDialogInfo();
 }
 
 void JavaScriptDialogTabHelper::CloseDialog(bool suppress_callback,
                                             bool success,
-                                            const base::string16& user_input) {
+                                            const base::string16& user_input,
+                                            DismissalCause cause) {
   DCHECK(dialog_);
+  LogDialogDismissalCause(cause);
 
   dialog_->CloseDialogWithoutCallback();
   if (!suppress_callback)
     dialog_callback_.Run(success, user_input);
 
   ClearDialogInfo();
 }
 
 void JavaScriptDialogTabHelper::ClearDialogInfo() {
   dialog_.reset();
   dialog_callback_.Reset();
   BrowserList::RemoveObserver(this);
 }