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_macros.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;
 
+  UMA_HISTOGRAM_ENUMERATION("DragDrop.Start", source,
+                            ui::DragDropTypes::DRAG_EVENT_SOURCE_COUNT);
+
   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) {
+      UMA_HISTOGRAM_ENUMERATION("DragDrop.Cancel", current_drag_event_source_,
+                                ui::DragDropTypes::DRAG_EVENT_SOURCE_COUNT);
       StartCanceledAnimation(kCancelAnimationDuration);
-    else
+    } else {
+      UMA_HISTOGRAM_ENUMERATION("DragDrop.Drop", current_drag_event_source_,
+                                ui::DragDropTypes::DRAG_EVENT_SOURCE_COUNT);
       drag_image_.reset();
+    }
   } else {
     drag_image_.reset();
   }
 
   Cleanup();
   if (should_block_during_drag_drop_)
     quit_closure_.Run();
 }
 
 void DragDropController::DragCancel() {
+  UMA_HISTOGRAM_ENUMERATION("DragDrop.Cancel", current_drag_event_source_,

[mfomitchev, 2015/01/14 17:03:41]

There is at least one case where DoDragCancel is called direactly, so we should
probably move the UMA logging there

[caelyn, 2015/01/21 16:29:53]

Done.

[mfomitchev, 2015/01/21 18:54:36]

Doesn't look like you've moved it. However look at my new comment - I think it
would be better to do it that way instead.

[caelyn, 2015/01/21 21:06:41]

Oops. I confused this with another thing and hit done by mistake.

+                            ui::DragDropTypes::DRAG_EVENT_SOURCE_COUNT);
   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 138 matching lines @@
 
 void DragDropController::AnimationEnded(const gfx::Animation* animation) {
   cancel_animation_.reset();
 
   // By the time we finish animation, another drag/drop session may have
   // started. We do not want to destroy the drag image in that case.
   if (!IsDragDropInProgress())
     drag_image_.reset();
   if (pending_long_tap_) {
     // If not in a nested message loop, we can forward the long tap right now.
-    if (!should_block_during_drag_drop_)
+    if (!should_block_during_drag_drop_) {
       ForwardPendingLongTap();
-    else {
+    } else {
       // See comment about this in OnGestureEvent().
       base::MessageLoopForUI::current()->PostTask(
           FROM_HERE,
           base::Bind(&DragDropController::ForwardPendingLongTap,
                      weak_factory_.GetWeakPtr()));
     }
   }
 }
 
 void DragDropController::DoDragCancel(int drag_cancel_animation_duration_ms) {
@@ skipping 51 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