refactor: use default printing path when no user options (#46587)

lib/browser/api/web-contents.ts

@@ -263,8 +263,17 @@ WebContents.prototype.print = function (options: ElectronInternal.WebContentsPri
     throw new TypeError('webContents.print(): Invalid print settings specified.');
   }
 
-  const pageSize = options.pageSize ?? 'A4';
-  if (typeof pageSize === 'object') {
+  const { pageSize } = options;
+  if (typeof pageSize === 'string' && PDFPageSizes[pageSize]) {
+    const mediaSize = PDFPageSizes[pageSize];
+    options.mediaSize = {
+      ...mediaSize,
+      imageable_area_left_microns: 0,
+      imageable_area_bottom_microns: 0,
+      imageable_area_right_microns: mediaSize.width_microns,
+      imageable_area_top_microns: mediaSize.height_microns
+    };
+  } else if (typeof pageSize === 'object') {
     if (!pageSize.height || !pageSize.width) {
       throw new Error('height and width properties are required for pageSize');
     }
@@ -286,16 +295,7 @@ WebContents.prototype.print = function (options: ElectronInternal.WebContentsPri
       imageable_area_right_microns: width,
       imageable_area_top_microns: height
     };
-  } else if (typeof pageSize === 'string' && PDFPageSizes[pageSize]) {
-    const mediaSize = PDFPageSizes[pageSize];
-    options.mediaSize = {
-      ...mediaSize,
-      imageable_area_left_microns: 0,
-      imageable_area_bottom_microns: 0,
-      imageable_area_right_microns: mediaSize.width_microns,
-      imageable_area_top_microns: mediaSize.height_microns
-    };
-  } else {
+  } else if (pageSize !== undefined) {
     throw new Error(`Unsupported pageSize: ${pageSize}`);
   }
 

shell/browser/api/electron_api_web_contents.cc

@@ -2944,9 +2944,8 @@ void OnGetDeviceNameToUse(base::WeakPtr<content::WebContents> web_contents,
     return;
   }
 
-  // If the user has passed a deviceName use it, otherwise use default printer.
+  // Use user-passed deviceName, otherwise default printer.
   print_settings.Set(printing::kSettingDeviceName, info.second);
-
   if (!print_settings.FindInt(printing::kSettingDpiHorizontal)) {
     gfx::Size dpi = GetDefaultPrinterDPI(info.second);
     print_settings.Set(printing::kSettingDpiHorizontal, dpi.width());
@@ -3005,6 +3004,17 @@ void WebContents::Print(gin::Arguments* args) {
     return;
   }
 
+  if (options.IsEmptyObject()) {
+    auto* print_view_manager =
+        PrintViewManagerElectron::FromWebContents(web_contents());
+    if (!print_view_manager)
+      return;
+
+    content::RenderFrameHost* rfh = GetRenderFrameHostToUse(web_contents());
+    print_view_manager->PrintNow(rfh, std::move(settings), std::move(callback));
+    return;
+  }
+
   // Set optional silent printing.
   bool silent = false;
   options.Get("silent", &silent);

shell/common/gin_helper/dictionary.h

@@ -183,6 +183,16 @@ class Dictionary : public gin::Dictionary {
 
   bool IsEmpty() const { return isolate() == nullptr || GetHandle().IsEmpty(); }
 
+  bool IsEmptyObject() const {
+    if (IsEmpty())
+      return true;
+
+    v8::Local<v8::Context> context = isolate()->GetCurrentContext();
+    v8::Local<v8::Array> props =
+        GetHandle()->GetOwnPropertyNames(context).ToLocalChecked();
+    return props->Length() == 0;
+  }
+
   v8::Local<v8::Object> GetHandle() const {
     return gin::ConvertToV8(isolate(),
                             *static_cast<const gin::Dictionary*>(this))