ui: Introduce CanvasPainter, remove PaintContext(gfx::Canvas*).

ui/views/controls/textfield/textfield.cc

Index: ui/views/controls/textfield/textfield.cc
diff --git a/ui/views/controls/textfield/textfield.cc b/ui/views/controls/textfield/textfield.cc
index 9e4111dd0fe1713489e27be3ca6d63faa8f20db2..e4e938806661afde0916f6575c331d875ec0921a 100644
--- a/ui/views/controls/textfield/textfield.cc
+++ b/ui/views/controls/textfield/textfield.cc
@@ -14,7 +14,7 @@
 #include "ui/base/dragdrop/drag_utils.h"
 #include "ui/base/touch/selection_bound.h"
 #include "ui/base/ui_base_switches_util.h"
-#include "ui/compositor/paint_context.h"
+#include "ui/compositor/canvas_painter.h"
 #include "ui/compositor/scoped_animation_duration_scale_mode.h"
 #include "ui/events/event.h"
 #include "ui/events/keycodes/keyboard_codes.h"
@@ -1075,6 +1075,7 @@ void Textfield::WriteDragDataForView(View* sender,
       GetDisplayNearestWindow(native_view);
   size.SetToMin(gfx::Size(display.size().width(), height()));
   label.SetBoundsRect(gfx::Rect(size));
+
   scoped_ptr<gfx::Canvas> canvas(
       GetCanvasForDragImage(GetWidget(), label.size()));
   label.SetEnabledColor(GetTextColor());
@@ -1082,7 +1083,7 @@ void Textfield::WriteDragDataForView(View* sender,
   // Desktop Linux Aura does not yet support transparency in drag images.
   canvas->DrawColor(GetBackgroundColor());
 #endif
-  label.Paint(ui::PaintContext(canvas.get()));
+  label.Paint(ui::CanvasPainter(canvas.get(), 1.f).context());
   const gfx::Vector2d kOffset(-15, 0);
   drag_utils::SetDragImageOnDataObject(*canvas, kOffset, data);
   if (controller_)