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"
@@ skipping 21 matching lines @@
 
 #if defined(OS_LINUX) && !defined(OS_CHROMEOS)
 #include <gnu/libc-version.h>
 
 #include "base/version.h"
 #if defined(USE_X11)
 #include "ui/base/x/x11_util.h"
 #endif
 #endif  // defined(OS_LINUX) && !defined(OS_CHROMEOS)
 
+#if defined(USE_OZONE) || defined(USE_X11)
+#include "ui/events/devices/device_data_manager.h"
+#include "ui/events/devices/input_device_event_observer.h"
+#endif  // defined(USE_OZONE) || defined(USE_X11)
+
 #if defined(OS_WIN)
 #include "chrome/installer/util/google_update_settings.h"
 #endif  // defined(OS_WIN)
 
 namespace {
 
 enum UMALinuxGlibcVersion {
   UMA_LINUX_GLIBC_NOT_PARSEABLE,
   UMA_LINUX_GLIBC_UNKNOWN,
   UMA_LINUX_GLIBC_2_11,
@@ skipping 188 matching lines @@
     state = UMA_TOUCH_EVENTS_DISABLED;
   } else {
     NOTREACHED();
     return;
   }
 
   UMA_HISTOGRAM_ENUMERATION("Touchscreen.TouchEventsEnabled", state,
                             UMA_TOUCH_EVENTS_STATE_COUNT);
 }
 
+#if defined(USE_OZONE) || defined(USE_X11)
+
+// Asynchronously records the touch event state when the ui::DeviceDataManager
+// completes a device scan.
+class AsynchronousTouchEventStateRecorder
+    : public ui::InputDeviceEventObserver {
+ public:
+  AsynchronousTouchEventStateRecorder();
+  ~AsynchronousTouchEventStateRecorder() override;
+
+  // ui::InputDeviceEventObserver overrides.
+  void OnDeviceListsComplete() override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(AsynchronousTouchEventStateRecorder);
+};
+
+AsynchronousTouchEventStateRecorder::AsynchronousTouchEventStateRecorder() {
+  ui::DeviceDataManager::GetInstance()->AddObserver(this);
+}
+
+AsynchronousTouchEventStateRecorder::~AsynchronousTouchEventStateRecorder() {
+  ui::DeviceDataManager::GetInstance()->RemoveObserver(this);
+}
+
+void AsynchronousTouchEventStateRecorder::OnDeviceListsComplete() {
+  ui::DeviceDataManager::GetInstance()->RemoveObserver(this);
+  RecordTouchEventState();
+}
+
+#endif  // defined(USE_OZONE) || defined(USE_X11)
+
 }  // namespace
 
 ChromeBrowserMainExtraPartsMetrics::ChromeBrowserMainExtraPartsMetrics()
     : display_count_(0), is_screen_observer_(false) {
 }
 
 ChromeBrowserMainExtraPartsMetrics::~ChromeBrowserMainExtraPartsMetrics() {
   if (is_screen_observer_)
     gfx::Screen::GetNativeScreen()->RemoveObserver(this);
 }
 
 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()) {
+    RecordTouchEventState();
+  } else {
+    input_device_event_observer_.reset(
+        new AsynchronousTouchEventStateRecorder());
+  }
+#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 36 matching lines @@
   }
 }
 
 namespace chrome {
 
 void AddMetricsExtraParts(ChromeBrowserMainParts* main_parts) {
   main_parts->AddParts(new ChromeBrowserMainExtraPartsMetrics());
 }
 
 }  // namespace chrome