Adding UMA stats for dragdrop events for both touch and mouse.

ash/drag_drop/drag_drop_controller.cc

 // Copyright (c) 2012 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 "ash/drag_drop/drag_drop_controller.h"
 
 #include "ash/drag_drop/drag_drop_tracker.h"
 #include "ash/drag_drop/drag_image_view.h"
 #include "ash/shell.h"
 #include "base/bind.h"
 #include "base/message_loop/message_loop.h"
+#include "base/metrics/histogram.h"
 #include "base/run_loop.h"
 #include "ui/aura/client/capture_client.h"
 #include "ui/aura/env.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_delegate.h"
 #include "ui/aura/window_event_dispatcher.h"
 #include "ui/base/dragdrop/drag_drop_types.h"
 #include "ui/base/dragdrop/os_exchange_data.h"
 #include "ui/base/hit_test.h"
 #include "ui/events/event.h"
@@ skipping 130 matching lines @@
     ui::DragDropTypes::DragEventSource source) {
   if (IsDragDropInProgress())
     return 0;
 
   const ui::OSExchangeData::Provider* provider = &data.provider();
   // We do not support touch drag/drop without a drag image.
   if (source == ui::DragDropTypes::DRAG_EVENT_SOURCE_TOUCH &&
       provider->GetDragImage().size().IsEmpty())
     return 0;
 
+  if (source == ui::DragDropTypes::DRAG_EVENT_SOURCE_TOUCH) {
+    UMA_HISTOGRAM_COUNTS("DragDrop.Touch.Start", 1);

[mfomitchev, 2015/01/08 23:30:59]

I think a single shared UMA_HISTOGRAM_ENUMERATION histogram would make more
sense here.

[caelyn, 2015/01/12 22:43:10]

I made the changes in histograms.xml and elsewhere - was that what you had in
mind?

+  } else if (source == ui::DragDropTypes::DRAG_EVENT_SOURCE_MOUSE) {
+    UMA_HISTOGRAM_COUNTS("DragDrop.Mouse.Start", 1);
+  }
+
   current_drag_event_source_ = source;
   DragDropTracker* tracker =
       new DragDropTracker(root_window, drag_drop_window_delegate_.get());
   if (source == ui::DragDropTypes::DRAG_EVENT_SOURCE_TOUCH) {
     // We need to transfer the current gesture sequence and the GR's touch event
     // queue to the |drag_drop_tracker_|'s capture window so that when it takes
     // capture, it still gets a valid gesture state.
     ui::GestureRecognizer::Get()->TransferEventsTo(source_window,
         tracker->capture_window());
     // We also send a gesture end to the source window so it can clear state.
@@ skipping 131 matching lines @@
     DragUpdate(target, event);
   DCHECK(target == drag_window_);
 
   aura::client::DragDropDelegate* delegate =
       aura::client::GetDragDropDelegate(target);
   if (delegate) {
     ui::DropTargetEvent e(
         *drag_data_, event.location(), event.root_location(), drag_operation_);
     e.set_flags(event.flags());
     drag_operation_ = delegate->OnPerformDrop(e);
-    if (drag_operation_ == 0)
+    if (drag_operation_ == 0) {
       StartCanceledAnimation(kCancelAnimationDuration);

[mfomitchev, 2015/01/08 23:30:59]

don't we need to log a Cancel here?

[caelyn, 2015/01/12 22:43:10]

Done. This changes the semantics of cancel to be logged whenever a DnD event
doesn't end in a drop event.

-    else
+    } else {
+      if (current_drag_event_source_ ==
+          ui::DragDropTypes::DRAG_EVENT_SOURCE_TOUCH) {
+        UMA_HISTOGRAM_COUNTS("DragDrop.Touch.Drop", 1);
+      } else if (current_drag_event_source_ ==
+                 ui::DragDropTypes::DRAG_EVENT_SOURCE_MOUSE) {
+        UMA_HISTOGRAM_COUNTS("DragDrop.Mouse.Drop", 1);
+      }
       drag_image_.reset();
+    }
   } else {
     drag_image_.reset();
   }
 
   Cleanup();
   if (should_block_during_drag_drop_)
     quit_closure_.Run();
 }
 
 void DragDropController::DragCancel() {
+  if (current_drag_event_source_ ==
+      ui::DragDropTypes::DRAG_EVENT_SOURCE_TOUCH) {
+    UMA_HISTOGRAM_COUNTS("DragDrop.Touch.Cancel", 1);
+  } else if (current_drag_event_source_ ==
+             ui::DragDropTypes::DRAG_EVENT_SOURCE_MOUSE) {
+    UMA_HISTOGRAM_COUNTS("DragDrop.Mouse.Cancel", 1);
+  }
   DoDragCancel(kCancelAnimationDuration);
 }
 
 bool DragDropController::IsDragDropInProgress() {
   return !!drag_drop_tracker_.get();
 }
 
 void DragDropController::OnKeyEvent(ui::KeyEvent* event) {
   if (IsDragDropInProgress() && event->key_code() == ui::VKEY_ESCAPE) {
     DragCancel();
@@ skipping 212 matching lines @@
   if (drag_window_)
     drag_window_->RemoveObserver(this);
   drag_window_ = NULL;
   drag_data_ = NULL;
   // Cleanup can be called again while deleting DragDropTracker, so delete
   // the pointer with a local variable to avoid double free.
   scoped_ptr<ash::DragDropTracker> holder = drag_drop_tracker_.Pass();
 }
 
 }  // namespace ash