Revert of Remove about:srcdoc url conversion.

content/browser/site_per_process_browsertest.cc

Index: content/browser/site_per_process_browsertest.cc
diff --git a/content/browser/site_per_process_browsertest.cc b/content/browser/site_per_process_browsertest.cc
index bdd1f8496bf07dba89ceee13c48729e0cdb8ea37..5e0a3e295f57422ac552dc5c5b2bfc1134d2f387 100644
--- a/content/browser/site_per_process_browsertest.cc
+++ b/content/browser/site_per_process_browsertest.cc
@@ -8774,7 +8774,7 @@
       "a.com", "/cross_site_iframe_factory.html?a(b)"));
   GURL child_url(embedded_test_server()->GetURL(
       "b.com", "/cross_site_iframe_factory.html?b()"));
-  GURL srcdoc_url(kAboutSrcDocURL);
+  GURL blank_url(url::kAboutBlankURL);
 
   // #1 Navigate to a page with a cross-site iframe.
   EXPECT_TRUE(NavigateToURL(shell(), parent_url));
@@ -8797,7 +8797,7 @@
   load_observer.Wait();
 
   // Ensure that the iframe reuses its parent's process.
-  EXPECT_EQ(srcdoc_url, child->current_url());
+  EXPECT_EQ(blank_url, child->current_url());
   EXPECT_EQ(root->current_frame_host()->GetSiteInstance(),
             child->current_frame_host()->GetSiteInstance());
   EXPECT_EQ(root->current_frame_host()->GetProcess(),