refactor: printToPDF should be headless (#33654)

shell/browser/api/electron_api_web_contents.cc

@@ -25,6 +25,7 @@
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/values.h"
 #include "chrome/browser/browser_process.h"
+#include "chrome/browser/printing/print_view_manager_base.h"
 #include "chrome/browser/ui/exclusive_access/exclusive_access_manager.h"
 #include "chrome/browser/ui/views/eye_dropper/eye_dropper.h"
 #include "chrome/common/pref_names.h"
@@ -165,9 +166,10 @@
 
 #if BUILDFLAG(ENABLE_PRINTING)
 #include "components/printing/browser/print_manager_utils.h"
+#include "components/printing/browser/print_to_pdf/pdf_print_utils.h"
 #include "printing/backend/print_backend.h"  // nogncheck
 #include "printing/mojom/print.mojom.h"      // nogncheck
-#include "shell/browser/printing/print_preview_message_handler.h"
+#include "printing/page_range.h"
 #include "shell/browser/printing/print_view_manager_electron.h"
 
 #if BUILDFLAG(IS_WIN)
@@ -919,10 +921,7 @@ void WebContents::InitWithWebContents(
   web_contents->SetDelegate(this);
 
 #if BUILDFLAG(ENABLE_PRINTING)
-  PrintPreviewMessageHandler::CreateForWebContents(web_contents.get());
   PrintViewManagerElectron::CreateForWebContents(web_contents.get());
-  printing::CreateCompositeClientIfNeeded(web_contents.get(),
-                                          browser_context->GetUserAgent());
 #endif
 
 #if BUILDFLAG(ENABLE_PDF_VIEWER)
@@ -2807,14 +2806,87 @@ void WebContents::Print(gin::Arguments* args) {
                      std::move(callback), device_name, silent));
 }
 
-v8::Local<v8::Promise> WebContents::PrintToPDF(base::DictionaryValue settings) {
+// Partially duplicated and modified from
+// headless/lib/browser/protocol/page_handler.cc;l=41
+v8::Local<v8::Promise> WebContents::PrintToPDF(const base::Value& settings) {
   v8::Isolate* isolate = JavascriptEnvironment::GetIsolate();
   gin_helper::Promise<v8::Local<v8::Value>> promise(isolate);
   v8::Local<v8::Promise> handle = promise.GetHandle();
-  PrintPreviewMessageHandler::FromWebContents(web_contents())
-      ->PrintToPDF(std::move(settings), std::move(promise));
+
+  // This allows us to track headless printing calls.
+  auto unique_id = settings.GetDict().FindInt(printing::kPreviewRequestID);
+  auto landscape = settings.GetDict().FindBool("landscape");
+  auto display_header_footer =
+      settings.GetDict().FindBool("displayHeaderFooter");
+  auto print_background = settings.GetDict().FindBool("shouldPrintBackgrounds");
+  auto scale = settings.GetDict().FindDouble("scale");
+  auto paper_width = settings.GetDict().FindInt("paperWidth");
+  auto paper_height = settings.GetDict().FindInt("paperHeight");
+  auto margin_top = settings.GetDict().FindIntByDottedPath("margins.top");
+  auto margin_bottom = settings.GetDict().FindIntByDottedPath("margins.bottom");
+  auto margin_left = settings.GetDict().FindIntByDottedPath("margins.left");
+  auto margin_right = settings.GetDict().FindIntByDottedPath("margins.right");
+  auto page_ranges = *settings.GetDict().FindString("pageRanges");
+  auto header_template = *settings.GetDict().FindString("headerTemplate");
+  auto footer_template = *settings.GetDict().FindString("footerTemplate");
+  auto prefer_css_page_size = settings.GetDict().FindBool("preferCSSPageSize");
+
+  absl::variant<printing::mojom::PrintPagesParamsPtr, std::string>
+      print_pages_params = print_to_pdf::GetPrintPagesParams(
+          web_contents()->GetMainFrame()->GetLastCommittedURL(), landscape,
+          display_header_footer, print_background, scale, paper_width,
+          paper_height, margin_top, margin_bottom, margin_left, margin_right,
+          absl::make_optional(header_template),
+          absl::make_optional(footer_template), prefer_css_page_size);
+
+  if (absl::holds_alternative<std::string>(print_pages_params)) {
+    auto error = absl::get<std::string>(print_pages_params);
+    promise.RejectWithErrorMessage("Invalid print parameters: " + error);
+    return handle;
+  }
+
+  auto* manager = PrintViewManagerElectron::FromWebContents(web_contents());
+  if (!manager) {
+    promise.RejectWithErrorMessage("Failed to find print manager");
+    return handle;
+  }
+
+  auto params = std::move(
+      absl::get<printing::mojom::PrintPagesParamsPtr>(print_pages_params));
+  params->params->document_cookie = unique_id.value_or(0);
+
+  manager->PrintToPdf(web_contents()->GetMainFrame(), page_ranges,
+                      std::move(params),
+                      base::BindOnce(&WebContents::OnPDFCreated, GetWeakPtr(),
+                                     std::move(promise)));
+
   return handle;
 }
+
+void WebContents::OnPDFCreated(
+    gin_helper::Promise<v8::Local<v8::Value>> promise,
+    PrintViewManagerElectron::PrintResult print_result,
+    scoped_refptr<base::RefCountedMemory> data) {
+  if (print_result != PrintViewManagerElectron::PrintResult::PRINT_SUCCESS) {
+    promise.RejectWithErrorMessage(
+        "Failed to generate PDF: " +
+        PrintViewManagerElectron::PrintResultToString(print_result));
+    return;
+  }
+
+  v8::Isolate* isolate = promise.isolate();
+  gin_helper::Locker locker(isolate);
+  v8::HandleScope handle_scope(isolate);
+  v8::Context::Scope context_scope(
+      v8::Local<v8::Context>::New(isolate, promise.GetContext()));
+
+  v8::Local<v8::Value> buffer =
+      node::Buffer::Copy(isolate, reinterpret_cast<const char*>(data->front()),
+                         data->size())
+          .ToLocalChecked();
+
+  promise.Resolve(buffer);
+}
 #endif
 
 void WebContents::AddWorkSpace(gin::Arguments* args,