Adding UMA logging to touch text selection

ui/views/touchui/touch_selection_controller_impl.cc

Index: ui/views/touchui/touch_selection_controller_impl.cc
diff --git a/ui/views/touchui/touch_selection_controller_impl.cc b/ui/views/touchui/touch_selection_controller_impl.cc
index 3ed8c0b388a13f595a20c1c04366ca391c2f899e..abfd6d9c93d1320ecc863dd5fc0e9e871cc636cf 100644
--- a/ui/views/touchui/touch_selection_controller_impl.cc
+++ b/ui/views/touchui/touch_selection_controller_impl.cc
@@ -4,6 +4,7 @@
 
 #include "ui/views/touchui/touch_selection_controller_impl.h"
 
+#include "base/metrics/histogram_macros.h"
 #include "base/time/time.h"
 #include "ui/aura/client/cursor_client.h"
 #include "ui/aura/env.h"
@@ -415,7 +416,9 @@ TouchSelectionControllerImpl::TouchSelectionControllerImpl(
                                            client_view->GetNativeView(),
                                            true)),
       context_menu_(nullptr),
+      command_executed_(false),
       dragging_handle_(nullptr) {
+  selection_start_time_ = base::TimeTicks::Now();
   aura::Window* client_window = client_view_->GetNativeView();
   client_window->AddObserver(this);
   client_widget_ = Widget::GetTopLevelWidgetForNativeView(client_window);
@@ -425,6 +428,8 @@ TouchSelectionControllerImpl::TouchSelectionControllerImpl(
 }
 
 TouchSelectionControllerImpl::~TouchSelectionControllerImpl() {
+  UMA_HISTOGRAM_BOOLEAN("Event.TouchSelectionEndedWithAction",
+                        command_executed_);
   HideContextMenu();
   aura::Env::GetInstance()->RemovePreTargetHandler(this);
   if (client_widget_)
@@ -594,6 +599,15 @@ bool TouchSelectionControllerImpl::IsCommandIdEnabled(int command_id) const {
 
 void TouchSelectionControllerImpl::ExecuteCommand(int command_id,
                                                   int event_flags) {
+  command_executed_ = true;
+  base::TimeDelta duration = base::TimeTicks::Now() - selection_start_time_;
+  // Note that we only log the duration stats for the 'successful' selections,
+  // i.e. selections ending with the execution of a command.
+  UMA_HISTOGRAM_CUSTOM_TIMES("Event.TouchSelectionDuration",
+                             duration,
+                             base::TimeDelta::FromMilliseconds(1000),

[Alexei Svitkine (slow), 2015/02/10 22:23:04]

Could you explain what kind of info you're hoping to get from these time
metrics?

Starting at 1s sounds like you will be missing a lot of details about the lower
end - but maybe that's what you want?

Or, perhaps it might be better to log the data in different units that
milliseconds, like e.g seconds or 100ms?

[jdduke (slow), 2015/02/10 22:29:00]

Yeah, I'm thinking we should at least go down to 500ms.

[mfomitchev, 2015/02/10 23:22:54]

Perhaps 1s is a bit low. I actually tried  before I chose 1s. The problem is
that with the logarithmic scale it takes something like 7 buckets for the value
to double, and we don't really need 7 buckets between 500ms and 1s, and we also
lose granularity at higher values unless we increase the total number of
buckets. The way I thought about it - anything at 1s or less is pretty awesome
UX for touch text selection. I don't know if we'd do anything differently if the
distribution in 500ms - 1s range changes. That said, I don't mind changing the
min to 500 and increasing the number of buckets to ~60 so that we can maintain a
decent granularity in the 1s-~10s range, which is the range I am mostly
interested in.
@asvitkine I guess I could log in 100ms units instead of in milliseconds - is
this a recommended practice in the cases where you don't need granularity higher
than 100ms? (Seconds would be too coarse here.) Is that done elsewhere?

+                             base::TimeDelta::FromSeconds(60),
+                             50);
   HideContextMenu();
   client_view_->ExecuteCommand(command_id, event_flags);
 }