fix: NPE in Page.pdf for persistent context (#1292)

Fixes #1291

Author: yury-s

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

@@ -946,9 +946,6 @@ public byte[] pdf(PdfOptions options) {
   }
 
   private byte[] pdfImpl(PdfOptions options) {
-    if (!browserContext.browser().isChromium()) {
-      throw new PlaywrightException("Page.pdf only supported in headless Chromium");
-    }
     if (options == null) {
       options = new PdfOptions();
     }

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

@@ -52,6 +52,18 @@ void shouldSupportFractionalScaleValue(@TempDir Path tempDir) throws IOException
   @DisabledIf(value="com.microsoft.playwright.TestBase#isChromium", disabledReason="skip")
   void shouldThrowInNonChromium() {
     PlaywrightException e = assertThrows(PlaywrightException.class, () -> page.pdf());
-    assertTrue(e.getMessage().contains("Page.pdf only supported in headless Chromium"));
+    assertTrue(e.getMessage().contains("PDF generation is only supported for Headless Chromium"), e.getMessage());
+  }
+
+
+  @Test
+  @DisabledIf(value="com.microsoft.playwright.TestBase#isChromium", disabledReason="skip")
+  void correctExceptionWithPersistentContext(@TempDir Path tempDir) {
+    Path profile = tempDir.resolve("profile");
+    try (BrowserContext context = browserType.launchPersistentContext(profile)) {
+      Page page = context.newPage();
+      PlaywrightException e = assertThrows(PlaywrightException.class, () -> page.pdf());
+      assertTrue(e.getMessage().contains("PDF generation is only supported for Headless Chromium"), e.getMessage());
+    }
   }
 }