Fixed the Touchscreen.TouchEventsEnabled histogram to record the correct values on X11 and Ozone ba…

chrome/browser/metrics/chrome_browser_main_extra_parts_metrics.cc

 // Copyright (c) 2013 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/metrics/chrome_browser_main_extra_parts_metrics.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/cpu.h"
 #include "base/metrics/histogram.h"
 #include "base/metrics/sparse_histogram.h"
 #include "base/sys_info.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "base/time/time.h"
 #include "chrome/browser/about_flags.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/chrome_browser_main.h"
 #include "chrome/browser/mac/bluetooth_utility.h"
 #include "chrome/browser/pref_service_flags_storage.h"
 #include "chrome/browser/shell_integration.h"
 #include "content/public/browser/browser_thread.h"
 #include "ui/base/touch/touch_device.h"
 #include "ui/base/ui_base_switches.h"
+#include "ui/events/devices/device_data_manager.h"
 #include "ui/events/event_switches.h"
 #include "ui/gfx/screen.h"
 
 #if defined(OS_ANDROID) && defined(__arm__)
 #include <cpu-features.h>
 #endif  // defined(OS_ANDROID) && defined(__arm__)
 
 #if defined(OS_LINUX) && !defined(OS_CHROMEOS)
 #include <gnu/libc-version.h>
 
@@ skipping 192 matching lines @@
       touch_enabled_switch == switches::kTouchEventsEnabled) {
     state = UMA_TOUCH_EVENTS_ENABLED;
   } else if (touch_enabled_switch == switches::kTouchEventsAuto) {
     state = ui::IsTouchDevicePresent() ?
         UMA_TOUCH_EVENTS_AUTO_ENABLED : UMA_TOUCH_EVENTS_AUTO_DISABLED;
   } else if (touch_enabled_switch == switches::kTouchEventsDisabled) {
     state = UMA_TOUCH_EVENTS_DISABLED;
   } else {
     NOTREACHED();
     return;
   }

[Ilya Sherman, 2015/06/24 23:46:50]

nit: Please revert the change to this line (i.e. restore the newline below it).

[bruthig, 2015/06/25 17:26:52]

Done.

-
   UMA_HISTOGRAM_ENUMERATION("Touchscreen.TouchEventsEnabled", state,
                             UMA_TOUCH_EVENTS_STATE_COUNT);
 }
 
 }  // namespace
 
 ChromeBrowserMainExtraPartsMetrics::ChromeBrowserMainExtraPartsMetrics()
     : display_count_(0), is_screen_observer_(false) {
 }
 
 ChromeBrowserMainExtraPartsMetrics::~ChromeBrowserMainExtraPartsMetrics() {
   if (is_screen_observer_)
     gfx::Screen::GetNativeScreen()->RemoveObserver(this);
+#if defined(USE_OZONE) || defined(USE_X11)
+  ui::DeviceDataManager::GetInstance()->RemoveObserver(this);

[Ilya Sherman, 2015/06/24 23:46:50]

Is it safe to call RemoveObserver() even if |this| is not currently registered
as an observer?

[bruthig, 2015/06/25 17:26:51]

That path is executed by the tests so I assume it is.

+#endif  // defined(USE_OZONE) || defined(USE_X11)
 }
 
 void ChromeBrowserMainExtraPartsMetrics::PreProfileInit() {
   RecordMicroArchitectureStats();
 }
 
 void ChromeBrowserMainExtraPartsMetrics::PreBrowserStart() {
   about_flags::PrefServiceFlagsStorage flags_storage_(
       g_browser_process->local_state());
   about_flags::RecordUMAStatistics(&flags_storage_);
 }
 
 void ChromeBrowserMainExtraPartsMetrics::PostBrowserStart() {
   RecordLinuxGlibcVersion();
 #if defined(USE_X11) && !defined(OS_CHROMEOS)
   UMA_HISTOGRAM_ENUMERATION("Linux.WindowManager",
                             GetLinuxWindowManager(),
                             UMA_LINUX_WINDOW_MANAGER_COUNT);
 #endif
+
+#if defined(USE_OZONE) || defined(USE_X11)
+  // The touch event state for X11 and Ozone based event sub-systems are based
+  // on device scans that happen asynchronously. So we may need to attach an
+  // observer to wait until these scans complete.
+  if (ui::DeviceDataManager::GetInstance()->device_lists_complete())
+    OnDeviceListsComplete();
+  else
+    ui::DeviceDataManager::GetInstance()->AddObserver(this);
+#else
   RecordTouchEventState();
+#endif  // defined(USE_OZONE) || defined(USE_X11)
 
 #if defined(OS_MACOSX) && !defined(OS_IOS)
   RecordMacMetrics();
 #endif  // defined(OS_MACOSX) && !defined(OS_IOS)
 
   const int kStartupMetricsGatheringDelaySeconds = 45;
   content::BrowserThread::GetBlockingPool()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&RecordStartupMetricsOnBlockingPool),
       base::TimeDelta::FromSeconds(kStartupMetricsGatheringDelaySeconds));
@@ skipping 21 matching lines @@
 
 void ChromeBrowserMainExtraPartsMetrics::OnDisplayMetricsChanged(
     const gfx::Display& display,
     uint32_t changed_metrics) {
 }
 
 void ChromeBrowserMainExtraPartsMetrics::ProfilerFinishedCollectingMetrics() {
   first_web_contents_profiler_.reset();
 }
 
+void ChromeBrowserMainExtraPartsMetrics::OnDeviceListsComplete() {
+  ui::DeviceDataManager::GetInstance()->RemoveObserver(this);
+  RecordTouchEventState();
+}
+
 void ChromeBrowserMainExtraPartsMetrics::EmitDisplaysChangedMetric() {
   int display_count = gfx::Screen::GetNativeScreen()->GetNumDisplays();
   if (display_count != display_count_) {
     display_count_ = display_count;
     UMA_HISTOGRAM_COUNTS_100("Hardware.Display.Count.OnChange", display_count_);
   }
 }
 
 namespace chrome {
 
 void AddMetricsExtraParts(ChromeBrowserMainParts* main_parts) {
   main_parts->AddParts(new ChromeBrowserMainExtraPartsMetrics());
 }
 
 }  // namespace chrome