Add UMA for the number of devices in the chooser when a device is paired

chrome/browser/ui/bluetooth/bluetooth_chooser_controller.cc

 // Copyright 2015 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/bluetooth/bluetooth_chooser_controller.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
 #include "base/metrics/histogram_macros.h"
@@ skipping 14 matching lines @@
   chrome::ScopedTabbedBrowserDisplayer browser_displayer(
       ProfileManager::GetActiveUserProfile());
   DCHECK(browser_displayer.browser());
   return browser_displayer.browser();
 }
 
 void RecordInteractionWithChooser(bool has_null_handler) {
   UMA_HISTOGRAM_BOOLEAN("Bluetooth.Web.ChooserInteraction", has_null_handler);
 }
 
+void RecordNumOfDevices(bool accept_all_devices, size_t num_of_devices) {
+  if (accept_all_devices) {
+    UMA_HISTOGRAM_SPARSE_SLOWLY(
+        "Bluetooth.Web.RequestDevice."
+        "NumOfDevicesInChooserWhenNotAcceptingAllDevices",
+        num_of_devices);

[Ilya Sherman, 2016/12/17 01:05:45]

Please cap the value that can be recorded here to something reasonable, like
100.

[juncai, 2016/12/19 20:17:57]

Done.

+  }
+}
+
 }  // namespace
 
 BluetoothChooserController::BluetoothChooserController(
     content::RenderFrameHost* owner,
-    const content::BluetoothChooser::EventHandler& event_handler)
+    const content::BluetoothChooser::EventHandler& event_handler,
+    bool accept_all_devices)
     : ChooserController(owner,
                         IDS_BLUETOOTH_DEVICE_CHOOSER_PROMPT_ORIGIN,
                         IDS_BLUETOOTH_DEVICE_CHOOSER_PROMPT_EXTENSION_NAME),
-      event_handler_(event_handler) {}
+      event_handler_(event_handler),
+      accept_all_devices_(accept_all_devices) {}
 
 BluetoothChooserController::~BluetoothChooserController() {}
 
 bool BluetoothChooserController::ShouldShowIconBeforeText() const {
   return true;
 }
 
 base::string16 BluetoothChooserController::GetNoOptionsText() const {
   return l10n_util::GetStringUTF16(
       IDS_BLUETOOTH_DEVICE_CHOOSER_NO_DEVICES_FOUND_PROMPT);
@@ skipping 54 matching lines @@
 }
 
 void BluetoothChooserController::Select(const std::vector<size_t>& indices) {
   DCHECK_EQ(1u, indices.size());
   size_t index = indices[0];
   RecordInteractionWithChooser(event_handler_.is_null());
   if (event_handler_.is_null()) {
     return;
   }
   DCHECK_LT(index, devices_.size());
+  RecordNumOfDevices(accept_all_devices_, devices_.size());
   event_handler_.Run(content::BluetoothChooser::Event::SELECTED,
                      devices_[index].id);
 }
 
 void BluetoothChooserController::Cancel() {
   RecordInteractionWithChooser(event_handler_.is_null());
   if (event_handler_.is_null())
     return;
   event_handler_.Run(content::BluetoothChooser::Event::CANCELLED,
                      std::string());
@@ skipping 143 matching lines @@
 
 void BluetoothChooserController::ResetEventHandler() {
   event_handler_.Reset();
 }
 
 void BluetoothChooserController::ClearAllDevices() {
   devices_.clear();
   device_id_to_name_map_.clear();
   device_name_counts_.clear();
 }