Label WebGPU swap buffers for improved PIX debugging

In PIX's D3D12-only mode, there is no way to determine frame
boundaries for WebGPU since Dawn does not manage DXGI swap chains.
Without assistance, PIX will wait forever for a present that never
happens.

If we know we're dealing with a swapbuffer texture, inform Dawn,
which informs PIX we've "presented" the texture so it can determine
frame boundaries and use the texture's contents for the UI.

Bug: dawn:364
Change-Id: I6b157a04df02be697dad6b5bc9d76c33969f9fda
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2124875Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Reviewed-by: Kai Ninomiya <kainino@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Commit-Queue: Rafael Cintron <rafael.cintron@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#755015}

gpu/command_buffer/common/shared_image_usage.h

@@ -37,6 +37,8 @@ enum SharedImageUsage : uint32_t {
   SHARED_IMAGE_USAGE_CONCURRENT_READ_WRITE = 1 << 9,
   // Image will be used for video decode acceleration on Chrome OS.
   SHARED_IMAGE_USAGE_VIDEO_DECODE = 1 << 10,
+  // Image will be used as a WebGPU swapbuffer
+  SHARED_IMAGE_USAGE_WEBGPU_SWAP_CHAIN_TEXTURE = 1 << 11,
 };
 
 }  // namespace gpu

gpu/command_buffer/service/shared_image_representation_d3d.cc

@@ -5,6 +5,7 @@
 #include "gpu/command_buffer/service/shared_image_representation_d3d.h"
 
 #include "components/viz/common/resources/resource_format_utils.h"
+#include "gpu/command_buffer/common/shared_image_usage.h"
 #include "gpu/command_buffer/service/shared_image_backing_d3d.h"
 
 namespace gpu {
@@ -93,6 +94,9 @@ WGPUTexture SharedImageRepresentationDawnD3D::BeginAccess(
   descriptor.isCleared = IsCleared();
   descriptor.sharedHandle = shared_handle;
   descriptor.acquireMutexKey = shared_mutex_acquire_key;
+  descriptor.isSwapChainTexture =
+      (d3d_image_backing->usage() &
+       SHARED_IMAGE_USAGE_WEBGPU_SWAP_CHAIN_TEXTURE);
 
   texture_ = dawn_native::d3d12::WrapSharedHandle(device_, &descriptor);
   if (texture_) {

third_party/blink/renderer/platform/graphics/gpu/webgpu_swap_buffer_provider.cc

@@ -95,7 +95,9 @@ WGPUTexture WebGPUSwapBufferProvider::GetNewTexture(const IntSize& size) {
   // TODO(cwallez@chromium.org): have some recycling mechanism.
   gpu::Mailbox mailbox = sii->CreateSharedImage(
       format_, static_cast<gfx::Size>(size), gfx::ColorSpace::CreateSRGB(),
-      gpu::SHARED_IMAGE_USAGE_WEBGPU | gpu::SHARED_IMAGE_USAGE_DISPLAY);
+      gpu::SHARED_IMAGE_USAGE_WEBGPU |
+          gpu::SHARED_IMAGE_USAGE_WEBGPU_SWAP_CHAIN_TEXTURE |
+          gpu::SHARED_IMAGE_USAGE_DISPLAY);
   gpu::SyncToken creation_token = sii->GenUnverifiedSyncToken();
 
   current_swap_buffer_ = base::AdoptRef(new SwapBuffer(