ozone/x11: Fix broken software compositing.

We used to be requesting a SkCanvas from the bitmap presenter and
creating own SkSurface for that canvas despite the fact that
X11BitmapSoftwarePresenter has already stored a SkSurface for
that canvas. This resulted in a weird behaviour - frames
were not presented.

So, instead of doing that roundtrip and looking for solutions for
creating a surface storage for that SkCanvas, change the
SurfaceOzoneCanvas to return SkCanvas instead of SkSurface.

This does not imply any behavioural changes.

Bug: 1045347
Change-Id: I09442a6019b1c073f4b1b3407c529792cf74c984
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2017432
Commit-Queue: Maksim Sisov <msisov@igalia.com>
Reviewed-by: Robert Kroeger <rjkroege@chromium.org>
Cr-Commit-Position: refs/heads/master@{#741369}

components/viz/service/display_embedder/software_output_device_ozone.cc

@@ -36,10 +36,10 @@ void SoftwareOutputDeviceOzone::Resize(const gfx::Size& viewport_pixel_size,
 SkCanvas* SoftwareOutputDeviceOzone::BeginPaint(const gfx::Rect& damage_rect) {
   DCHECK(gfx::Rect(viewport_pixel_size_).Contains(damage_rect));
 
-  // Get canvas for next frame.
-  surface_ = surface_ozone_->GetSurface();
+  damage_rect_ = damage_rect;
 
-  return SoftwareOutputDevice::BeginPaint(damage_rect);
+  // Get canvas for next frame.
+  return surface_ozone_->GetCanvas();
 }
 
 void SoftwareOutputDeviceOzone::EndPaint() {

ui/ozone/demo/software_renderer.cc

@@ -57,12 +57,12 @@ void SoftwareRenderer::RenderFrame() {
 
   float fraction = NextFraction();
 
-  sk_sp<SkSurface> surface = software_surface_->GetSurface();
+  SkCanvas* canvas = software_surface_->GetCanvas();
 
   SkColor color =
       SkColorSetARGB(0xff, 0, 0xff * fraction, 0xff * (1 - fraction));
 
-  surface->getCanvas()->clear(color);
+  canvas->clear(color);
 
   software_surface_->PresentCanvas(gfx::Rect(size_));
 

ui/ozone/platform/cast/surface_factory_cast.cc

@@ -26,7 +26,7 @@ class DummySurface : public SurfaceOzoneCanvas {
   ~DummySurface() override {}
 
   // SurfaceOzoneCanvas implementation:
-  sk_sp<SkSurface> GetSurface() override { return surface_; }
+  SkCanvas* GetCanvas() override { return surface_->getCanvas(); }
 
   void ResizeCanvas(const gfx::Size& viewport_size) override {
     surface_ =

ui/ozone/platform/headless/headless_surface_factory.cc

@@ -75,7 +75,7 @@ class FileSurface : public SurfaceOzoneCanvas {
     surface_ = SkSurface::MakeRaster(SkImageInfo::MakeN32Premul(
         viewport_size.width(), viewport_size.height()));
   }
-  sk_sp<SkSurface> GetSurface() override { return surface_; }
+  SkCanvas* GetCanvas() override { return surface_->getCanvas(); }
   void PresentCanvas(const gfx::Rect& damage) override {
     if (base_path_.empty())
       return;

ui/ozone/platform/scenic/scenic_window_canvas.cc

@@ -83,7 +83,7 @@ void ScenicWindowCanvas::ResizeCanvas(const gfx::Size& viewport_size) {
   }
 }
 
-sk_sp<SkSurface> ScenicWindowCanvas::GetSurface() {
+SkCanvas* ScenicWindowCanvas::GetCanvas() {
   if (viewport_size_.IsEmpty() || frames_[current_frame_].is_empty())
     return nullptr;
 
@@ -108,7 +108,7 @@ sk_sp<SkSurface> ScenicWindowCanvas::GetSurface() {
     }
   }
 
-  return frames_[current_frame_].surface;
+  return frames_[current_frame_].surface->getCanvas();
 }
 
 void ScenicWindowCanvas::PresentCanvas(const gfx::Rect& damage) {

ui/ozone/platform/scenic/scenic_window_canvas.h

@@ -17,6 +17,8 @@
 #include "ui/ozone/platform/scenic/scenic_surface_factory.h"
 #include "ui/ozone/public/surface_ozone_canvas.h"
 
+class SkSurface;
+
 namespace scenic {
 class Session;
 }  // namespace scenic
@@ -36,7 +38,7 @@ class ScenicWindowCanvas : public SurfaceOzoneCanvas {
 
   // SurfaceOzoneCanvas implementation.
   void ResizeCanvas(const gfx::Size& viewport_size) override;
-  sk_sp<SkSurface> GetSurface() override;
+  SkCanvas* GetCanvas() override;
   void PresentCanvas(const gfx::Rect& damage) override;
   std::unique_ptr<gfx::VSyncProvider> CreateVSyncProvider() override;
 

ui/ozone/platform/wayland/gpu/wayland_canvas_surface.cc

@@ -170,7 +170,7 @@ WaylandCanvasSurface::~WaylandCanvasSurface() {
   buffer_manager_->UnregisterSurface(widget_);
 }
 
-sk_sp<SkSurface> WaylandCanvasSurface::GetSurface() {
+SkCanvas* WaylandCanvasSurface::GetCanvas() {
   DCHECK(!pending_buffer_)
       << "The previous pending buffer has not been presented yet";
 
@@ -197,7 +197,7 @@ sk_sp<SkSurface> WaylandCanvasSurface::GetSurface() {
 
   DCHECK(pending_buffer_);
   pending_buffer_->OnUse();
-  return pending_buffer_->sk_surface();
+  return pending_buffer_->sk_surface()->getCanvas();
 }
 
 void WaylandCanvasSurface::ResizeCanvas(const gfx::Size& viewport_size) {

ui/ozone/platform/wayland/gpu/wayland_canvas_surface.h

@@ -15,6 +15,8 @@
 #include "ui/ozone/platform/wayland/gpu/wayland_surface_gpu.h"
 #include "ui/ozone/public/surface_ozone_canvas.h"
 
+class SkCanvas;
+
 namespace ui {
 
 class WaylandBufferManagerGpu;
@@ -31,7 +33,7 @@ class WaylandCanvasSurface : public SurfaceOzoneCanvas,
   ~WaylandCanvasSurface() override;
 
   // SurfaceOzoneCanvas
-  sk_sp<SkSurface> GetSurface() override;
+  SkCanvas* GetCanvas() override;
   void ResizeCanvas(const gfx::Size& viewport_size) override;
   void PresentCanvas(const gfx::Rect& damage) override;
   std::unique_ptr<gfx::VSyncProvider> CreateVSyncProvider() override;

ui/ozone/platform/wayland/gpu/wayland_surface_factory_unittest.cc

@@ -132,7 +132,8 @@ TEST_P(WaylandSurfaceFactoryTest, Canvas) {
   ASSERT_TRUE(canvas);
 
   canvas->ResizeCanvas(window_->GetBounds().size());
-  canvas->GetSurface();
+  auto* sk_canvas = canvas->GetCanvas();
+  DCHECK(sk_canvas);
   canvas->PresentCanvas(gfx::Rect(5, 10, 20, 15));
 
   // Wait until the mojo calls are done.
@@ -161,9 +162,11 @@ TEST_P(WaylandSurfaceFactoryTest, CanvasResize) {
   ASSERT_TRUE(canvas);
 
   canvas->ResizeCanvas(window_->GetBounds().size());
-  canvas->GetSurface();
+  auto* sk_canvas = canvas->GetCanvas();
+  DCHECK(sk_canvas);
   canvas->ResizeCanvas(gfx::Size(100, 50));
-  canvas->GetSurface();
+  sk_canvas = canvas->GetCanvas();
+  DCHECK(sk_canvas);
   canvas->PresentCanvas(gfx::Rect(0, 0, 100, 50));
 
   base::RunLoop().RunUntilIdle();

ui/ozone/platform/x11/x11_canvas_surface.cc

@@ -21,16 +21,12 @@ X11CanvasSurface::X11CanvasSurface(
 
 X11CanvasSurface::~X11CanvasSurface() = default;
 
-sk_sp<SkSurface> X11CanvasSurface::GetSurface() {
-  DCHECK(surface_);
-  return surface_;
+SkCanvas* X11CanvasSurface::GetCanvas() {
+  return x11_software_bitmap_presenter_.GetSkCanvas();
 }
 
 void X11CanvasSurface::ResizeCanvas(const gfx::Size& viewport_size) {
   x11_software_bitmap_presenter_.Resize(viewport_size);
-  SkImageInfo info = SkImageInfo::MakeN32(
-      viewport_size.width(), viewport_size.height(), kOpaque_SkAlphaType);
-  surface_ = x11_software_bitmap_presenter_.GetSkCanvas()->makeSurface(info);
 }
 
 void X11CanvasSurface::PresentCanvas(const gfx::Rect& damage) {

ui/ozone/platform/x11/x11_canvas_surface.h

@@ -18,6 +18,8 @@
 #include "ui/gfx/native_widget_types.h"
 #include "ui/ozone/public/surface_ozone_canvas.h"
 
+class SkSurface;
+
 namespace ui {
 
 // The platform-specific part of an software output. The class is intended
@@ -31,7 +33,7 @@ class X11CanvasSurface : public SurfaceOzoneCanvas {
   ~X11CanvasSurface() override;
 
   // SurfaceOzoneCanvas overrides:
-  sk_sp<SkSurface> GetSurface() override;
+  SkCanvas* GetCanvas() override;
   void ResizeCanvas(const gfx::Size& viewport_size) override;
   void PresentCanvas(const gfx::Rect& damage) override;
   std::unique_ptr<gfx::VSyncProvider> CreateVSyncProvider() override;

ui/ozone/public/surface_ozone_canvas.h

@@ -11,7 +11,7 @@
 #include "base/component_export.h"
 #include "third_party/skia/include/core/SkRefCnt.h"
 
-class SkSurface;
+class SkCanvas;
 
 namespace gfx {
 class Rect;
@@ -29,8 +29,11 @@ class COMPONENT_EXPORT(OZONE_BASE) SurfaceOzoneCanvas {
  public:
   virtual ~SurfaceOzoneCanvas();
 
-  // Returns an SkSurface for drawing on the window.
-  virtual sk_sp<SkSurface> GetSurface() = 0;
+  // Returns an SkCanvas for drawing on the window. The SurfaceOzoneCanvas keeps
+  // the SkCanvas alive until the client finishes writing contents and calls
+  // PresentCanvas. Additionally, the SkCanvas becomes invalid after
+  // ResizeCanvas is called. See comment at ResizeCanvas.
+  virtual SkCanvas* GetCanvas() = 0;
 
   // Attempts to resize the canvas to match the viewport size. After
   // resizing, the compositor must call GetSurface() to get the next