Ensure that the drag image during drag drop operations on Windows is of the correct scale.

ui/base/dragdrop/drag_utils_win.cc

Index: ui/base/dragdrop/drag_utils_win.cc
diff --git a/ui/base/dragdrop/drag_utils_win.cc b/ui/base/dragdrop/drag_utils_win.cc
index 9fedd4202a34ac8e32614fd9de5b9d15a07b8407..e2c5b601bdcd93373c20f964d2edd19ce1070af8 100644
--- a/ui/base/dragdrop/drag_utils_win.cc
+++ b/ui/base/dragdrop/drag_utils_win.cc
@@ -18,9 +18,14 @@
 #include "ui/gfx/geometry/size.h"
 #include "ui/gfx/image/image_skia.h"
 #include "ui/gfx/skbitmap_operations.h"
+#include "ui/gfx/win/dpi.h"
 
 namespace drag_utils {
 
+// The DragDropHelper object on Windows supports images with width upto 300 px.
+// Images with widths more than that are clipped.
+const int kMaxDragImageWidth = 300;
+
 static void SetDragImageOnDataObject(HBITMAP hbitmap,
                                      const gfx::Size& size_in_pixels,
                                      const gfx::Vector2d& cursor_offset,
@@ -31,9 +36,13 @@ static void SetDragImageOnDataObject(HBITMAP hbitmap,
   if (SUCCEEDED(rv)) {
     SHDRAGIMAGE sdi;
     sdi.sizeDragImage = size_in_pixels.ToSIZE();
+    sdi.sizeDragImage.cx =
+        std::min<int>(kMaxDragImageWidth, sdi.sizeDragImage.cx);

[ananta, 2015/12/01 02:47:07]

If the width is more than 300 the bitmap is displayed clipped but is still
better than what we see today. Once the blink fix lands it should be better.

     sdi.crColorKey = 0xFFFFFFFF;
     sdi.hbmpDragImage = hbitmap;
-    sdi.ptOffset = gfx::PointAtOffsetFromOrigin(cursor_offset).ToPOINT();
+    gfx::Point point_at_offset_in_pixels = gfx::win::DIPToScreenPoint(
+        gfx::PointAtOffsetFromOrigin(cursor_offset));
+    sdi.ptOffset = point_at_offset_in_pixels.ToPOINT();
     helper->InitializeFromBitmap(&sdi, data_object);
   }
 }