Adding UMA logging to touch text selection

ui/touch_selection/touch_selection_controller.cc

Index: ui/touch_selection/touch_selection_controller.cc
diff --git a/ui/touch_selection/touch_selection_controller.cc b/ui/touch_selection/touch_selection_controller.cc
index d53f4095e05195aa24e52ff1f6ea2a45770a8632..0f512060e68f39b8c2c928f05943b8f85c6c2a44 100644
--- a/ui/touch_selection/touch_selection_controller.cc
+++ b/ui/touch_selection/touch_selection_controller.cc
@@ -6,6 +6,7 @@
 
 #include "base/auto_reset.h"
 #include "base/logging.h"
+#include "base/metrics/histogram_macros.h"
 
 namespace ui {
 namespace {
@@ -55,12 +56,15 @@ TouchSelectionController::TouchSelectionController(
       activate_selection_automatically_(false),
       selection_empty_(false),
       selection_editable_(false),
-      temporarily_hidden_(false) {
+      temporarily_hidden_(false),
+      selection_handle_dragged_(false) {
   DCHECK(client_);
   HideAndDisallowShowingAutomatically();
 }
 
 TouchSelectionController::~TouchSelectionController() {

[jdduke (slow), 2015/02/10 17:50:25]

I'm not sure we ought to count this case, as this will occur if the tab is
closed, a cross-origin navigation occurs or the page crashes. I dunno.

[mfomitchev, 2015/02/10 19:05:23]

Sure. Got rid of this.

+  if (is_selection_active_)
+    LogSelectionEnd();
 }
 
 void TouchSelectionController::OnSelectionBoundsChanged(
@@ -239,6 +243,7 @@ void TouchSelectionController::OnHandleDragBegin(const TouchHandle& handle) {
     base = start_selection_handle_->position() + GetStartLineOffset();
     extent = end_selection_handle_->position() + GetEndLineOffset();
   }
+  selection_handle_dragged_ = true;
 
   // When moving the handle we want to move only the extent point. Before doing
   // so we must make sure that the base point is set correctly.
@@ -385,7 +390,13 @@ void TouchSelectionController::ActivateSelection() {
   // an entirely new selection, notify the client but avoid sending an
   // intervening SELECTION_CLEARED update to avoid unnecessary state changes.
   if (!is_selection_active_ || response_pending_input_event_ == LONG_PRESS) {
+    if (is_selection_active_) {
+      // The active selection session finishes with the start of the new one.
+      LogSelectionEnd();
+    }
     is_selection_active_ = true;
+    selection_handle_dragged_ = false;
+    selection_start_time_ = base::TimeTicks::Now();
     response_pending_input_event_ = INPUT_EVENT_TYPE_NONE;
     client_->OnSelectionEvent(SELECTION_SHOWN, GetStartPosition());
   }
@@ -396,6 +407,7 @@ void TouchSelectionController::DeactivateSelection() {
     return;
   DCHECK(start_selection_handle_);
   DCHECK(end_selection_handle_);
+  LogSelectionEnd();
   start_selection_handle_->SetEnabled(false);
   end_selection_handle_->SetEnabled(false);
   is_selection_active_ = false;
@@ -442,4 +454,19 @@ TouchHandle::AnimationStyle TouchSelectionController::GetAnimationStyle(
              : TouchHandle::ANIMATION_NONE;
 }
 
+void TouchSelectionController::LogSelectionEnd() {
+  // TODO(mfomitchev): Once we are able to tell the difference between
+  // 'successful' and 'unsuccessful' selections - log
+  // Event.TouchSelectionDuration instead and get rid of
+  // Event.TouchDragSelectionDuration.
+  if (selection_handle_dragged_) {
+    base::TimeDelta duration = base::TimeTicks::Now() - selection_start_time_;
+    UMA_HISTOGRAM_CUSTOM_TIMES("Event.TouchDragSelectionDuration",
+                               duration,
+                               base::TimeDelta::FromMilliseconds(1),
+                               base::TimeDelta::FromSeconds(60),
+                               50);

[jdduke (slow), 2015/02/10 17:50:25]

Is this enough buckets to get the granularity we want?

[mfomitchev, 2015/02/10 19:05:23]

That's a good point. The time scale is logarithmic by default, so I had a ton of
buckets from 1ms to 100ms, which was a total waste. I changed the min to be
1000ms, which makes things a lot better: at 1s the granularity is 90ms, at 3s it
is 300ms, at 10s it is 900ms, and the last bucket is ~5s. I think that's pretty
reasonable.

[jdduke (slow), 2015/02/10 19:08:05]

Ah, I didn't realize it was logarithmic, thanks.

+  }
+}
+
 }  // namespace ui