Change call-sites now that SkCanvas is not ref-counted

ui/gfx/canvas.h

 // 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.
 
 #ifndef UI_GFX_CANVAS_H_
 #define UI_GFX_CANVAS_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 71 matching lines @@
   Canvas();
 
   // Creates canvas with provided DIP |size| and |image_scale|.
   // If this canvas is not opaque, it's explicitly cleared to transparent before
   // being returned.
   Canvas(const Size& size, float image_scale, bool is_opaque);
 
   // Creates a Canvas backed by an |sk_canvas| with |image_scale_|.
   // |sk_canvas| is assumed to be already scaled based on |image_scale|
   // so no additional scaling is applied.
-  Canvas(sk_sp<SkCanvas> sk_canvas, float image_scale);
+  // Note: the caller must ensure that sk_canvas outlives this object, or until
+  // RecreateBackingCanvas is called.
+  Canvas(SkCanvas* sk_canvas, float image_scale);
 
   virtual ~Canvas();
 
   // Recreates the backing platform canvas with DIP |size| and |image_scale_|.
   // If the canvas is not opaque, it is explicitly cleared.
   // This method is public so that canvas_skia_paint can recreate the platform
   // canvas after having initialized the canvas.
   // TODO(pkotwicz): Push the image_scale into skia::PlatformCanvas such that
   // this method can be private.
   void RecreateBackingCanvas(const Size& size,
@@ skipping 371 matching lines @@
   // Apply transformation on the canvas.
   void Transform(const Transform& transform);
 
   // Draws the given string with a fade gradient at the end.
   void DrawFadedString(const base::string16& text,
                        const FontList& font_list,
                        SkColor color,
                        const Rect& display_rect,
                        int flags);
 
-  SkCanvas* sk_canvas() { return canvas_.get(); }
+  SkCanvas* sk_canvas() { return canvas_; }
   float image_scale() const { return image_scale_; }
 
  private:
   // Tests whether the provided rectangle intersects the current clip rect.
   bool IntersectsClipRect(const SkRect& rect);
 
   // Helper for the DrawImageInt functions declared above. The
   // |remove_image_scale| parameter indicates if the scale of the |image_rep|
   // should be removed when drawing the image, to avoid double-scaling it.
   void DrawImageIntHelper(const ImageSkiaRep& image_rep,
                           int src_x,
                           int src_y,
                           int src_w,
                           int src_h,
                           int dest_x,
                           int dest_y,
                           int dest_w,
                           int dest_h,
                           bool filter,
                           const SkPaint& paint,
                           bool remove_image_scale);
 
   // The device scale factor at which drawing on this canvas occurs.
   // An additional scale can be applied via Canvas::Scale(). However,
   // Canvas::Scale() does not affect |image_scale_|.
   float image_scale_;
 
-  sk_sp<SkCanvas> canvas_;
+  // canvas_ is our active canvas object. Sometimes we are also the owner,
+  // in which case canvas_owner_ will be set. Other times we are just
+  // borrowing someone else's canvas, in which case canvas_ will point there
+  // but canvas_owner_ will be null.
+  std::unique_ptr<SkCanvas> canvas_owner_;
+  SkCanvas* canvas_;
 
   DISALLOW_COPY_AND_ASSIGN(Canvas);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_CANVAS_H_