Use animated vector icon for app menu notification animation.

ui/gfx/paint_vector_icon.h

 // Copyright 2015 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_PAINT_VECTOR_ICON_H_
 #define UI_GFX_PAINT_VECTOR_ICON_H_
 
 #include "base/time/time.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/gfx/gfx_export.h"
 #include "ui/gfx/image/image_skia.h"
 
 namespace gfx {
 
 class Canvas;
 struct VectorIcon;
 
+// Describes an instance of an icon: an icon definition and a set of drawing
+// parameters.
+struct GFX_EXPORT IconDescription {
+  IconDescription(const IconDescription& other);
+
+  IconDescription(const VectorIcon& icon,
+                  int dip_size,
+                  SkColor color,
+                  const base::TimeDelta& elapsed_time,
+                  const VectorIcon& badge_icon);
+
+  ~IconDescription();
+
+  bool operator<(const IconDescription& other) const;

[sadrul, 2017/05/23 18:01:14]

I don't think < operator makes sense for IconDescription.

[Evan Stade, 2017/05/23 23:38:42]

Why not? This is just used as an ordering operation so we can use it as a key in
a map.

[sadrul, 2017/05/24 17:35:14]

I don't know what the result of comparing two non-animated IconDescription of
the same size + dip + color would mean.

Can you use a std::unordered_map() with a hash-function instead?

[Evan Stade, 2017/05/24 17:47:53]

Does it matter what the meaning of the comparison is? It just imposes a
deterministic ordering.
Aren't we supposed to avoid hash maps?

[sadrul, 2017/05/26 19:50:27]

Let's create a separate function for that, then, and not override < operator.
Can you link that explains why?

[Evan Stade, 2017/05/26 20:48:52]

I moved this to a separate struct, although I'd still like to understand why
that's important. We define operator< for the sake of std:: data structures a
lot, e.g. in gfx::Point, gfx::Rect, gfx::ColorSpace. When should we avoid it and
when is it ok?
https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/rdxOHKzQmRY

+
+  const VectorIcon& icon;
+  int dip_size;
+  SkColor color;
+  const base::TimeDelta elapsed_time;
+  const VectorIcon& badge_icon;
+};
+
 GFX_EXPORT extern const VectorIcon kNoneIcon;
 
 // Draws a vector icon identified by |id| onto |canvas| at (0, 0). |color| is
 // used as the fill. The size will come from the .icon file (the 1x version, if
 // multiple versions exist). |elapsed_time| is used to determine the state of
 // any transitions the icon may define.
 GFX_EXPORT void PaintVectorIcon(
     Canvas* canvas,
     const VectorIcon& icon,
     SkColor color,
     const base::TimeDelta& elapsed_time = base::TimeDelta());
 
 // As above, with a specificed size. |dip_size| is the length of a single edge
 // of the square icon, in device independent pixels.
 GFX_EXPORT void PaintVectorIcon(
     Canvas* canvas,
     const VectorIcon& icon,
     int dip_size,
     SkColor color,
     const base::TimeDelta& elapsed_time = base::TimeDelta());
 
+// Creates an ImageSkia which will render the icon on demand.
+// TODO(estade): update clients to use this version and remove the other
+// CreateVectorIcon()s.
+GFX_EXPORT ImageSkia CreateVectorIcon(const IconDescription& params);
+
 // Creates an ImageSkia which will render the icon on demand. The size will come
 // from the .icon file (the 1x version, if multiple versions exist).
 GFX_EXPORT ImageSkia CreateVectorIcon(const VectorIcon& icon, SkColor color);
 
 // As above, but creates the image at the given size.
 GFX_EXPORT ImageSkia CreateVectorIcon(const VectorIcon& icon,
                                       int dip_size,
                                       SkColor color);
 
 // As above, but also paints a badge defined by |badge_id| on top of the icon.
@@ skipping 15 matching lines @@
 // Calculates the size that will be default for |icon|, in dip.
 GFX_EXPORT int GetDefaultSizeOfVectorIcon(const gfx::VectorIcon& icon);
 
 // Calculates and returns the elapsed time at which all animations/transitions
 // will be finished.
 base::TimeDelta GetDurationOfAnimation(const VectorIcon& icon);
 
 }  // namespace gfx
 
 #endif  // UI_GFX_PAINT_VECTOR_ICON_H_