Add PDFExtensionTest.DownloadPDFButton

components/pdf/browser/pdf_web_contents_helper.cc

Index: components/pdf/browser/pdf_web_contents_helper.cc
diff --git a/components/pdf/browser/pdf_web_contents_helper.cc b/components/pdf/browser/pdf_web_contents_helper.cc
index ae931d4eae78087c42e5789eb558fd1159f0f436..94605b0c5745e7f1f8215b37ed38ae4deb9187d0 100644
--- a/components/pdf/browser/pdf_web_contents_helper.cc
+++ b/components/pdf/browser/pdf_web_contents_helper.cc
@@ -41,6 +41,11 @@ void PDFWebContentsHelper::ShowOpenInReaderPrompt(
   UpdateLocationBar();
 }
 
+void PDFWebContentsHelper::SetClientForTest(
+    std::unique_ptr<PDFWebContentsHelperClient> client) {
+  client_ = std::move(client);
+}
+
 bool PDFWebContentsHelper::OnMessageReceived(
     const IPC::Message& message,
     content::RenderFrameHost* render_frame_host) {