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

ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11.cc

Index: ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11.cc
diff --git a/ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11.cc b/ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11.cc
index 5bad49a3bfda60fb4783aedf8e67fcec32dd3f88..a4957cbbbf23c85b464bf8cb63fb46a839475b14 100644
--- a/ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11.cc
+++ b/ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11.cc
@@ -9,6 +9,7 @@
 #include "base/event_types.h"
 #include "base/lazy_instance.h"
 #include "base/message_loop/message_loop.h"
+#include "base/metrics/histogram.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "ui/aura/client/capture_client.h"
 #include "ui/aura/window.h"
@@ -417,6 +418,7 @@ DesktopDragDropClientAuraX11::DesktopDragDropClientAuraX11(
       source_current_window_(None),
       source_state_(SOURCE_STATE_OTHER),
       drag_operation_(0),
+      current_drag_event_source_(ui::DragDropTypes::DRAG_EVENT_SOURCE_MOUSE),
       negotiated_operation_(ui::DragDropTypes::DRAG_NONE),
       weak_ptr_factory_(this) {
   // Some tests change the DesktopDragDropClientAuraX11 associated with an
@@ -645,6 +647,12 @@ int DesktopDragDropClientAuraX11::StartDragAndDrop(
     const gfx::Point& root_location,
     int operation,
     ui::DragDropTypes::DragEventSource source) {
+  if (source == ui::DragDropTypes::DRAG_EVENT_SOURCE_TOUCH) {
+    UMA_HISTOGRAM_COUNTS("DragDrop.Touch.Start", 1);
+  } else if (source == ui::DragDropTypes::DRAG_EVENT_SOURCE_MOUSE) {
+    UMA_HISTOGRAM_COUNTS("DragDrop.Mouse.Start", 1);
+  }
+
   source_current_window_ = None;
   DCHECK(!g_current_drag_drop_client);
   g_current_drag_drop_client = this;
@@ -654,6 +662,7 @@ int DesktopDragDropClientAuraX11::StartDragAndDrop(
   source_state_ = SOURCE_STATE_OTHER;
   drag_operation_ = operation;
   negotiated_operation_ = ui::DragDropTypes::DRAG_NONE;
+  current_drag_event_source_ = source;
 
   const ui::OSExchangeData::Provider* provider = &data.provider();
   source_provider_ = static_cast<const ui::OSExchangeDataProviderAuraX11*>(
@@ -790,6 +799,13 @@ void DesktopDragDropClientAuraX11::OnMouseReleased() {
 
       // We have negotiated an action with the other end.
       source_state_ = SOURCE_STATE_DROPPED;
+      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);
+      }
       SendXdndDrop(source_current_window_);
       return;
     }