Fix SkR+Dawn NOTIMPLEMENTED

Fix NOTIMPLEMENTED() that gets hit with SkiaRenderer+Dawn for max
texture size. There is no API to query max texture size but WebGPU needs
to support 8k textures so that is a safe placeholder for now.

Bug: 1090476
Change-Id: Ia25ab3441b717410f09e21bb3785413c8a3c097a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2225624
Auto-Submit: kylechar <kylechar@chromium.org>
Commit-Queue: Khushal <khushalsagar@chromium.org>
Reviewed-by: Khushal <khushalsagar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#774362}

gpu/command_buffer/service/raster_decoder.cc

@@ -948,6 +948,10 @@ Capabilities RasterDecoderImpl::GetCapabilities() {
 #else
     NOTREACHED();
 #endif
+  } else if (shared_context_state_->GrContextIsDawn()) {
+    // TODO(crbug.com/1090476): Query Dawn for this value once an API exists for
+    // capabilities.
+    caps.max_texture_size = 8192;
   } else {
     NOTIMPLEMENTED();
   }