Revert of Remove about:srcdoc url conversion.

chrome/browser/extensions/api/web_navigation/frame_navigation_state.cc

Index: chrome/browser/extensions/api/web_navigation/frame_navigation_state.cc
diff --git a/chrome/browser/extensions/api/web_navigation/frame_navigation_state.cc b/chrome/browser/extensions/api/web_navigation/frame_navigation_state.cc
index 2519c77975befbc745670dc1fc64d6bd9531188c..fe50acfe06243f0a44818817b06e449302e33baa 100644
--- a/chrome/browser/extensions/api/web_navigation/frame_navigation_state.cc
+++ b/chrome/browser/extensions/api/web_navigation/frame_navigation_state.cc
@@ -30,6 +30,7 @@
 
 FrameNavigationState::FrameState::FrameState() {
   error_occurred = false;
+  is_iframe_srcdoc = false;
   is_loading = false;
   is_parsing = false;
 }
@@ -70,10 +71,13 @@
     content::RenderFrameHost* frame_host,
     const GURL& url,
     bool is_same_page,
-    bool is_error_page) {
+    bool is_error_page,
+    bool is_iframe_srcdoc) {
   FrameState& frame_state = frame_host_state_map_[frame_host];
   frame_state.error_occurred = is_error_page;
   frame_state.url = url;
+  frame_state.is_iframe_srcdoc = is_iframe_srcdoc;
+  DCHECK(!is_iframe_srcdoc || url == url::kAboutBlankURL);
   if (!is_same_page) {
     frame_state.is_loading = true;
     frame_state.is_parsing = true;
@@ -112,6 +116,8 @@
   if (it == frame_host_state_map_.end())
     return GURL();
 
+  if (it->second.is_iframe_srcdoc)
+    return GURL(content::kAboutSrcDocURL);
   return it->second.url;
 }