[Thumbnails] Specify copy size in Pixels, not DIPs

chrome/browser/thumbnails/thumbnailing_algorithm.h

 // Copyright (c) 2013 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 CHROME_BROWSER_THUMBNAILS_THUMBNAILING_ALGORITHM_H_
 #define CHROME_BROWSER_THUMBNAILS_THUMBNAILING_ALGORITHM_H_
 
 #include "base/memory/ref_counted.h"
 #include "chrome/browser/thumbnails/thumbnailing_context.h"
 #include "ui/base/layout.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/geometry/size.h"
 
 class SkBitmap;
 
 namespace thumbnails {
 
 // An interface abstracting thumbnailing algorithms. Instances are intended to
 // be created by ThumbnailService's implementations and used by
 // ThumbnailTabHelper as consumers of captured source images.
 class ThumbnailingAlgorithm
     : public base::RefCountedThreadSafe<ThumbnailingAlgorithm> {
  public:
   typedef base::Callback<void(const ThumbnailingContext&, const SkBitmap&)>
       ConsumerCallback;
   // Provides information necessary to crop-and-resize image data from a source
   // canvas of |source_size|. Auxiliary |scale_factor| helps compute the target

[Lei Zhang, 2015/03/26 18:34:56]

The comments still refer to target and |target_size| even though you have
changed the variable name.

[Mathieu, 2015/03/26 21:19:48]

Done.

-  // thumbnail size. Parameters of the required copy operation are assigned to
-  // |clipping_rect| (cropping rectangle for the source canvas) and
-  // |target_size| (the size of the target bitmap).
-  // The return value indicates the type of clipping that will be done.
+  // thumbnail size to be copied from the backing store, in pixels. Parameters
+  // of the required copy operation are assigned to |clipping_rect| (cropping
+  // rectangle for the source canvas) and |target_size| (the size of the target
+  // bitmap in pixels). The return value indicates the type of clipping that
+  // will be done.
   virtual ClipResult GetCanvasCopyInfo(const gfx::Size& source_size,
                                        ui::ScaleFactor scale_factor,
                                        gfx::Rect* clipping_rect,
-                                       gfx::Size* target_size) const = 0;
+                                       gfx::Size* copy_size) const = 0;
 
   // Invoked to produce a thumbnail image from a |bitmap| extracted by the
   // callee from source canvas according to instructions provided by a call
   // to GetCanvasCopyInfo.
   // Note that ProcessBitmap must be able to handle bitmaps which might have not
   // been processed (scalled/cropped) as requested. |context| gives additional
   // information on the source, including if and how it was clipped.
   // The function shall invoke |callback| once done, passing in fully populated
   // |context| along with resulting thumbnail bitmap.
   virtual void ProcessBitmap(scoped_refptr<ThumbnailingContext> context,
                              const ConsumerCallback& callback,
                              const SkBitmap& bitmap) = 0;
 
  protected:
   virtual ~ThumbnailingAlgorithm() {}
   friend class base::RefCountedThreadSafe<ThumbnailingAlgorithm>;
 };
 
-}
+}  // namespace thumbnails
 
 #endif  // CHROME_BROWSER_THUMBNAILS_THUMBNAILING_ALGORITHM_H_