[M115] webcodecs: Stop using async VideoFrame.copyTo() for WebGPU arr…

…ay buffers

ArrayBufferContents from GPUMappedDOMArrayBuffer doesn't really own
the underlying buffer, that's why default implementation of
ShareNonSharedForInternalUse() doesn't make sense.

(cherry picked from commit 8e8d780)

Bug: 1447839
Change-Id: Iecf7abcb202aa79fa7775814677d7dc5c9ed558b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4575395
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Eugene Zemtsov <eugene@chromium.org>
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Reviewed-by: Austin Eng <enga@chromium.org>
Cr-Original-Commit-Position: refs/heads/main@{#1151466}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4585217
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/branch-heads/5790@{#391}
Cr-Branched-From: 1d71a33-refs/heads/main@{#1148114}

third_party/blink/renderer/core/typed_arrays/dom_array_buffer.cc

@@ -116,6 +116,15 @@ bool DOMArrayBuffer::Transfer(v8::Isolate* isolate,
   return true;
 }
 
+bool DOMArrayBuffer::ShareNonSharedForInternalUse(ArrayBufferContents& result) {
+  if (!Content()->BackingStore()) {
+    result.Detach();
+    return false;
+  }
+  Content()->ShareNonSharedForInternalUse(result);
+  return true;
+}
+
 v8::Maybe<bool> DOMArrayBuffer::TransferDetachable(
     v8::Isolate* isolate,
     v8::Local<v8::Value> detach_key,

third_party/blink/renderer/core/typed_arrays/dom_array_buffer.h

@@ -79,16 +79,9 @@ class CORE_EXPORT DOMArrayBuffer : public DOMArrayBufferBase {
                 ExceptionState& exception_state);
 
   // Share the ArrayBuffer, even if it is non-shared. Such sharing is necessary
-  // for e.g. WebAudio which uses a separate thread for processing the
-  // ArrayBuffer while at the same time exposing a NonShared Float32Array.
-  bool ShareNonSharedForInternalUse(ArrayBufferContents& result) {
-    if (!Content()->BackingStore()) {
-      result.Detach();
-      return false;
-    }
-    Content()->ShareNonSharedForInternalUse(result);
-    return true;
-  }
+  // for e.g. WebAudio and WebCodecs which use a separate thread for processing
+  // the ArrayBuffer while at the same time exposing a NonShared TypedArray.
+  virtual bool ShareNonSharedForInternalUse(ArrayBufferContents& result);
 
   v8::MaybeLocal<v8::Value> Wrap(ScriptState*) override;
 

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

@@ -16,18 +16,20 @@ ArrayBufferContents PinArrayBufferContent(
         if (buffer->IsShared()) {
           buffer->Content()->ShareWith(result);
         } else {
-          buffer->Content()->ShareNonSharedForInternalUse(result);
+          static_cast<blink::DOMArrayBuffer*>(buffer)
+              ->ShareNonSharedForInternalUse(result);
         }
       }
       return result;
     }
     case AllowSharedBufferSource::ContentType::kArrayBufferViewAllowShared: {
       auto* view = buffer_union->GetAsArrayBufferViewAllowShared().Get();
       if (view && !view->IsDetached()) {
-        if (view->IsShared())
+        if (view->IsShared()) {
           view->BufferShared()->Content()->ShareWith(result);
-        else
-          view->buffer()->Content()->ShareNonSharedForInternalUse(result);
+        } else {
+          view->buffer()->ShareNonSharedForInternalUse(result);
+        }
       }
       return result;
     }

third_party/blink/renderer/modules/webgpu/gpu_buffer.cc

@@ -100,6 +100,13 @@ class GPUMappedDOMArrayBuffer : public DOMArrayBuffer {
     CHECK(result && IsDetached());
   }
 
+  // Due to an unusual non-owning backing these array buffers can't be shared
+  // for internal use.
+  bool ShareNonSharedForInternalUse(ArrayBufferContents& result) override {
+    result.Detach();
+    return false;
+  }
+
   void Trace(Visitor* visitor) const override {
     DOMArrayBuffer::Trace(visitor);
     visitor->Trace(owner_);