[ptheads] Rename receiveObjectTransfer. NFC (emscripten-core#23641)

Followup to emscripten-core#14875.

The name receiveObjectTransfer implies that all kinds of things can be
received but its really only for the offscreen canvas.

Author: sbc100

src/lib/libpthread.js

@@ -203,17 +203,17 @@ var LibraryPThread = {
       // linear memory.
       __emscripten_thread_free_data(pthread_ptr);
     },
-    receiveObjectTransfer(data) {
 #if OFFSCREENCANVAS_SUPPORT
+    receiveOffscreenCanvases(data) {
       if (typeof GL != 'undefined') {
         Object.assign(GL.offscreenCanvases, data.offscreenCanvases);
         if (!Module['canvas'] && data.moduleCanvasId && GL.offscreenCanvases[data.moduleCanvasId]) {
           Module['canvas'] = GL.offscreenCanvases[data.moduleCanvasId].offscreenCanvas;
           Module['canvas'].id = data.moduleCanvasId;
         }
       }
-#endif
     },
+#endif
     // Called by worker.js each time a thread is started.
     threadInitTLS() {
 #if PTHREADS_DEBUG

src/runtime_pthread.js

@@ -157,7 +157,9 @@ if (ENVIRONMENT_IS_PTHREAD) {
         // Pass the thread address to wasm to store it for fast access.
         __emscripten_thread_init(msgData.pthread_ptr, /*is_main=*/0, /*is_runtime=*/0, /*can_block=*/1, 0, 0);
 
-        PThread.receiveObjectTransfer(msgData);
+#if OFFSCREENCANVAS_SUPPORT
+        PThread.receiveOffscreenCanvases(msgData);
+#endif
         PThread.threadInitTLS();
 
         // Await mailbox notifications with `Atomics.waitAsync` so we can start