Add API in gfx::Canvas for Skottie

This patch adds an API to gfx::Canvas to draw skottie directly on the
backing canvas. It also removes the bitmap rasterization of each
animation frame from the ui thread and offloads it to cc.

Bug: 890224
Change-Id: Ibf8d9b682428be26c12caa4cccaae9bd53bb255a
Component: gfx, canvas, skia vector animation
Reviewed-on: https://chromium-review.googlesource.com/c/1292527
Commit-Queue: Malay Keshav <malaykeshav@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#601419}

ui/gfx/canvas.cc

@@ -441,6 +441,12 @@ void Canvas::DrawImageInPath(const ImageSkia& image,
   canvas_->drawPath(path, flags);
 }
 
+void Canvas::DrawSkottie(scoped_refptr<cc::SkottieWrapper> skottie,
+                         const Rect& dst,
+                         float t) {
+  canvas_->drawSkottie(std::move(skottie), RectToSkRect(dst), t);
+}
+
 void Canvas::DrawStringRect(const base::string16& text,
                             const FontList& font_list,
                             SkColor color,

ui/gfx/canvas.h

@@ -20,6 +20,10 @@
 #include "ui/gfx/native_widget_types.h"
 #include "ui/gfx/text_constants.h"
 
+namespace cc {
+class SkottieWrapper;
+}  // namespace cc
+
 namespace gfx {
 
 class Rect;
@@ -360,6 +364,13 @@ class GFX_EXPORT Canvas {
                        const SkPath& path,
                        const cc::PaintFlags& flags);
 
+  // Draws the frame of the |skottie| animation specified by the normalized time
+  // instant t [0->first frame .. 1->last frame] onto the region corresponded by
+  // |dst| in the canvas.
+  void DrawSkottie(scoped_refptr<cc::SkottieWrapper> skottie,
+                   const Rect& dst,
+                   float t);
+
   // Draws text with the specified color, fonts and location. The text is
   // aligned to the left, vertically centered, clipped to the region. If the
   // text is too big, it is truncated and '...' is added to the end.

ui/gfx/skia_vector_animation.cc

@@ -204,23 +204,9 @@ void SkiaVectorAnimation::Paint(gfx::Canvas* canvas,
 void SkiaVectorAnimation::PaintFrame(gfx::Canvas* canvas,
                                      float t,
                                      const gfx::Size& size) {
-  TRACE_EVENT0("ui", "SkiaVectorAnimation Paint");
   DCHECK_GE(t, 0.f);
   DCHECK_LE(t, 1.f);
-
-  float scale = canvas->UndoDeviceScaleFactor();
-  gfx::Size pixel_size = gfx::ScaleToRoundedSize(size, scale);
-
-  SkBitmap bitmap;
-  bitmap.allocN32Pixels(std::round(pixel_size.width()),
-                        std::round(pixel_size.height()), false);
-  SkCanvas skcanvas(bitmap);
-  skcanvas.clear(SK_ColorTRANSPARENT);
-
-  skottie_->Draw(&skcanvas, t,
-                 SkRect::MakeWH(pixel_size.width(), pixel_size.height()));
-
-  canvas->DrawImageInt(gfx::ImageSkia::CreateFrom1xBitmap(bitmap), 0, 0);
+  canvas->DrawSkottie(skottie(), gfx::Rect(size), t);
 }
 
 void SkiaVectorAnimation::InitTimer(const base::TimeTicks& timestamp) {