Shadow DOM container for popup iframes (#623)

* Add support for injecting stylesheets into a custom parent node

* Add api.getStylesheetContent

* Add support for injecting a CSS file's content

* Add usePopupShadowDom option

* Use a per-parentNode cache

* Add support for using a shadow DOM wrapper around popup iframes

* Ignore the popup container instead of the frame

1 files changed, 8 insertions, 0 deletions

diff --git a/ext/bg/js/backend.js b/ext/bg/js/backend.js
index b89cb641..344706d1 100644
--- a/ext/bg/js/backend.js
+++ b/ext/bg/js/backend.js
@@ -108,6 +108,7 @@ class Backend {
             ['broadcastTab',                 {async: false, contentScript: true,  handler: this._onApiBroadcastTab.bind(this)}],
             ['frameInformationGet',          {async: true,  contentScript: true,  handler: this._onApiFrameInformationGet.bind(this)}],
             ['injectStylesheet',             {async: true,  contentScript: true,  handler: this._onApiInjectStylesheet.bind(this)}],
+            ['getStylesheetContent',         {async: true,  contentScript: true,  handler: this._onApiGetStylesheetContent.bind(this)}],
             ['getEnvironmentInfo',           {async: false, contentScript: true,  handler: this._onApiGetEnvironmentInfo.bind(this)}],
             ['clipboardGet',                 {async: true,  contentScript: true,  handler: this._onApiClipboardGet.bind(this)}],
             ['getDisplayTemplatesHtml',      {async: true,  contentScript: true,  handler: this._onApiGetDisplayTemplatesHtml.bind(this)}],
@@ -719,6 +720,13 @@ class Backend {
         });
     }
 
+    async _onApiGetStylesheetContent({url}) {
+        if (!url.startsWith('/') || url.startsWith('//') || !url.endsWith('.css')) {
+            throw new Error('Invalid URL');
+        }
+        return await requestText(url, 'GET');
+    }
+
     _onApiGetEnvironmentInfo() {
         return this.environment.getInfo();
     }