don't override processed frames

lib/single-file/frame-tree.js

@@ -89,17 +89,19 @@ this.frameTree = this.frameTree || (() => {
 					frameData = { windowId: messageFrameData.windowId };
 					windowData.frames.push(frameData);
 				}
-				frameData.content = messageFrameData.content;
-				frameData.baseURI = messageFrameData.baseURI;
-				frameData.title = messageFrameData.title;
-				frameData.stylesheetContents = messageFrameData.stylesheetContents;
-				frameData.responsiveImageData = messageFrameData.responsiveImageData;
-				frameData.imageData = messageFrameData.imageData;
-				frameData.postersData = messageFrameData.postersData;
-				frameData.canvasData = messageFrameData.canvasData;
-				frameData.fontsData = messageFrameData.fontsData;
-				frameData.processed = messageFrameData.processed;
-				frameData.timeout = messageFrameData.timeout;
+				if (!frameData.processed) {
+					frameData.content = messageFrameData.content;
+					frameData.baseURI = messageFrameData.baseURI;
+					frameData.title = messageFrameData.title;
+					frameData.stylesheetContents = messageFrameData.stylesheetContents;
+					frameData.responsiveImageData = messageFrameData.responsiveImageData;
+					frameData.imageData = messageFrameData.imageData;
+					frameData.postersData = messageFrameData.postersData;
+					frameData.canvasData = messageFrameData.canvasData;
+					frameData.fontsData = messageFrameData.fontsData;
+					frameData.processed = messageFrameData.processed;
+					frameData.timeout = messageFrameData.timeout;
+				}
 			});
 			const remainingFrames = windowData.frames.filter(frameData => !frameData.processed).length;
 			if (!remainingFrames) {