cherry-pick(#1469): fix: put file payloads into "payloads" protocol f… (#1470)

Reference #1468

Author: yury-s

playwright/src/main/java/com/microsoft/playwright/impl/ElementHandleImpl.java

@@ -490,7 +490,7 @@ void setInputFilesImpl(FilePayload[] files, SetInputFilesOptions options) {
       options = new SetInputFilesOptions();
     }
     JsonObject params = gson().toJsonTree(options).getAsJsonObject();
-    params.add("files", Serialization.toJsonArray(files));
+    params.add("payloads", Serialization.toJsonArray(files));
     sendMessage("setInputFiles", params);
   }
 

playwright/src/test/java/com/microsoft/playwright/TestPageSetInputFiles.java

@@ -308,7 +308,18 @@ void shouldAcceptSingleFile() {
     assertEquals("file-to-upload.txt", page.evalOnSelector("input", "input => input.files[0].name"));
   }
 
-//  @Test
+  @Test
+  void shouldAcceptSingleFilePayload() {
+    page.setContent("<input type=file oninput='javascript:console.timeStamp()'>");
+    FileChooser fileChooser = page.waitForFileChooser(() -> page.click("input"));
+    assertEquals(page, fileChooser.page());
+    assertNotNull(fileChooser.element());
+    fileChooser.setFiles(new FilePayload("test.txt", "text/plain", "Hello!".getBytes()));
+    assertEquals(1, page.evalOnSelector("input", "input => input.files.length"));
+    assertEquals("test.txt", page.evalOnSelector("input", "input => input.files[0].name"));
+  }
+
+  //  @Test
   void shouldDetectMimeType() throws ExecutionException, InterruptedException {
     // TODO: Parse form fields on server
   }