Revert of Remove about:srcdoc url conversion.

content/browser/frame_host/frame_tree_browsertest.cc

Index: content/browser/frame_host/frame_tree_browsertest.cc
diff --git a/content/browser/frame_host/frame_tree_browsertest.cc b/content/browser/frame_host/frame_tree_browsertest.cc
index 7906007a8496278f179a3f597e91cf5435439893..8dea25ba20e1561141b0b1ef95b87244ea13658c 100644
--- a/content/browser/frame_host/frame_tree_browsertest.cc
+++ b/content/browser/frame_host/frame_tree_browsertest.cc
@@ -486,7 +486,7 @@
     EXPECT_EQ(2U, root->child_count());
     observer.Wait();
 
-    EXPECT_EQ(GURL(kAboutSrcDocURL), root->child_at(1)->current_url());
+    EXPECT_EQ(GURL(url::kAboutBlankURL), root->child_at(1)->current_url());
     EXPECT_TRUE(ExecuteScriptAndExtractString(
         root->child_at(1), "domAutomationController.send(document.origin);",
         &frame_origin));
@@ -505,7 +505,7 @@
     EXPECT_TRUE(ExecuteScript(root, script));
     observer.Wait();
 
-    EXPECT_EQ(GURL(kAboutSrcDocURL), child->current_url());
+    EXPECT_EQ(GURL(url::kAboutBlankURL), child->current_url());
     EXPECT_TRUE(ExecuteScriptAndExtractString(
         child, "domAutomationController.send(document.origin);",
         &frame_origin));