[webcodecs] Support VideoFrame.createImageBitmap() in workers

Creation of ImageBitmaps from VideoFrames is implemented using a
viz::RasterContextProvider in //media. Such a thing is available
from Platform on the main thread, but not in workers.

This CL exposes the underlying viz::RasterContextProvider from
WebGraphicsContext3DProvider so that the //media code can be called
using the SharedGpuContext context.

Bug: 1148849
Change-Id: Ie69e84e423f7e6f4aca13b7b86bcf178b3e15958
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2570331
Commit-Queue: Dan Sanders <sandersd@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Reviewed-by: Chrome Cunningham <chcunningham@chromium.org>
Cr-Commit-Position: refs/heads/master@{#833949}

content/renderer/webgraphicscontext3d_provider_impl.cc

@@ -198,7 +198,12 @@ void WebGraphicsContext3DProviderImpl::CopyVideoFrame(
     media::PaintCanvasVideoRenderer* video_renderer,
     media::VideoFrame* video_frame,
     cc::PaintCanvas* canvas) {
-  video_renderer->Copy(video_frame, canvas, context_provider());
+  video_renderer->Copy(video_frame, canvas, provider_.get());
+}
+
+viz::RasterContextProvider*
+WebGraphicsContext3DProviderImpl::RasterContextProvider() const {
+  return provider_.get();
 }
 
 }  // namespace content

content/renderer/webgraphicscontext3d_provider_impl.h

@@ -57,10 +57,7 @@ class CONTENT_EXPORT WebGraphicsContext3DProviderImpl
   void CopyVideoFrame(media::PaintCanvasVideoRenderer* video_render,
                       media::VideoFrame* video_frame,
                       cc::PaintCanvas* canvas) override;
-
-  viz::ContextProviderCommandBuffer* context_provider() const {
-    return provider_.get();
-  }
+  viz::RasterContextProvider* RasterContextProvider() const override;
 
  private:
   // viz::ContextLostObserver implementation.

third_party/blink/public/platform/web_graphics_context_3d_provider.h

@@ -65,7 +65,11 @@ class RasterInterface;
 namespace webgpu {
 class WebGPUInterface;
 }
-}
+}  // namespace gpu
+
+namespace viz {
+class RasterContextProvider;
+}  // namespace viz
 
 namespace blink {
 enum AntialiasingMode {
@@ -111,6 +115,7 @@ class WebGraphicsContext3DProvider {
   virtual void CopyVideoFrame(media::PaintCanvasVideoRenderer* video_render,
                               media::VideoFrame* video_frame,
                               cc::PaintCanvas* canvas) = 0;
+  virtual viz::RasterContextProvider* RasterContextProvider() const = 0;
 };
 
 }  // namespace blink

third_party/blink/renderer/modules/webcodecs/video_frame.cc

@@ -6,6 +6,7 @@
 
 #include <utility>
 
+#include "base/memory/scoped_refptr.h"
 #include "components/viz/common/gpu/raster_context_provider.h"
 #include "components/viz/common/resources/single_release_callback.h"
 #include "gpu/command_buffer/client/shared_image_interface.h"
@@ -454,20 +455,20 @@ ScriptPromise VideoFrame::CreateImageBitmap(ScriptState* script_state,
           SkImage::MakeRasterData(info, image_pixels, bytes_per_row);
       image = UnacceleratedStaticBitmapImage::Create(std::move(skImage));
     } else {
-      if (!IsMainThread()) {
-        // TODO(crbug.com/1148849): We should either hop to the media thread and
-        // use the media context, or use the SharedGpuContext. Currently
-        // obtaining the media context requires synchronizing with the main
-        // thread, and PaintCanvasVideoRenderer is not compatible with
-        // SharedGpuContext.
+      scoped_refptr<viz::RasterContextProvider> raster_context_provider;
+      base::WeakPtr<WebGraphicsContext3DProviderWrapper> wrapper =
+          SharedGpuContext::ContextProviderWrapper();
+      if (wrapper && wrapper->ContextProvider()) {
+        raster_context_provider = base::WrapRefCounted(
+            wrapper->ContextProvider()->RasterContextProvider());
+      }
+      if (!raster_context_provider) {
         exception_state.ThrowDOMException(DOMExceptionCode::kOperationError,
                                           "Graphics context unavailable.");
         return ScriptPromise();
       }
-      scoped_refptr<viz::RasterContextProvider> raster_context_provider =
-          Platform::Current()->SharedMainThreadContextProvider();
-      auto* ri = raster_context_provider->RasterInterface();
 
+      auto* ri = raster_context_provider->RasterInterface();
       gpu::SharedImageInterface* shared_image_interface =
           raster_context_provider->SharedImageInterface();
       uint32_t usage = gpu::SHARED_IMAGE_USAGE_GLES2;

third_party/blink/renderer/platform/graphics/gpu/drawing_buffer_test_helpers.h

@@ -74,6 +74,9 @@ class WebGraphicsContext3DProviderForTests
   void CopyVideoFrame(media::PaintCanvasVideoRenderer* video_render,
                       media::VideoFrame* video_frame,
                       cc::PaintCanvas* canvas) override {}
+  viz::RasterContextProvider* RasterContextProvider() const override {
+    return nullptr;
+  }
 
  private:
   cc::StubDecodeCache image_decode_cache_;

third_party/blink/renderer/platform/graphics/test/fake_web_graphics_context_3d_provider.h

@@ -90,6 +90,9 @@ class FakeWebGraphicsContext3DProvider : public WebGraphicsContext3DProvider {
   void CopyVideoFrame(media::PaintCanvasVideoRenderer* video_render,
                       media::VideoFrame* video_frame,
                       cc::PaintCanvas* canvas) override {}
+  viz::RasterContextProvider* RasterContextProvider() const override {
+    return nullptr;
+  }
 
  private:
   cc::StubDecodeCache stub_image_decode_cache_;