UMA stats for stylus usage

chrome/browser/ui/views/frame/browser_frame.cc

Index: chrome/browser/ui/views/frame/browser_frame.cc
diff --git a/chrome/browser/ui/views/frame/browser_frame.cc b/chrome/browser/ui/views/frame/browser_frame.cc
index 2cbb1850d2cc9227c5a68f16dd03fb9444b420f8..b84738a88e1383a9943133173305e0057f9d51df 100644
--- a/chrome/browser/ui/views/frame/browser_frame.cc
+++ b/chrome/browser/ui/views/frame/browser_frame.cc
@@ -35,6 +35,7 @@
 #if defined(OS_CHROMEOS)
 #include "ash/common/session/session_state_delegate.h"  // nogncheck
 #include "ash/common/wm_shell.h"  // nogncheck
+#include "chrome/browser/ui/ash/metrics/stylus_metrics_recorder_chromeos.h"
 #include "ui/native_theme/native_theme_dark_aura.h"  // nogncheck
 #endif
 
@@ -99,6 +100,12 @@ void BrowserFrame::InitBrowserFrame() {
 
   Init(params);
 
+#if defined(OS_CHROMEOS)
+  browser_view_->GetNativeWindow()->SetProperty(
+      chromeos::kStylusWindowTypeBucket,
+      chromeos::StylusWindowType::WINDOW_TYPE_BROWSER_WINDOW);

[sky, 2016/09/16 23:20:17]

This also includes things like popups. Are you sure you want them lumped with
BROWSER_WINDOWS? Also, move this to BrowserNonClientFrameViewAsh as that is the
only place that really cares about it.

[xiaoyinh(OOO Sep 11-29), 2016/09/19 21:19:53]

Moved to BrowserNonClientFrameViewAsh::Init()

I feel that popup windows could also be counted as down events on browser window
because it happens during the web browsing. Let me know if you think otherwise. 

If we are going to rule out the popup, could I use widget type TYPE_POPUP to
check it?

[sky, 2016/09/19 23:36:53]

I'm not familiar with what you're considering 'browser' window. I wanted to make
sure you were aware this code is hit for popups too. If you want popups in that
too, that's fine. If you want to rule out popups you would check the browser
type. In fact the browser type may include apps. See Browser::is_app().

+#endif
+
   if (!native_browser_frame_->UsesNativeSystemMenu()) {
     DCHECK(non_client_view());
     non_client_view()->set_context_menu_controller(this);