Remove about:srcdoc url conversion.

content/browser/frame_host/render_frame_host_manager.cc

Index: content/browser/frame_host/render_frame_host_manager.cc
diff --git a/content/browser/frame_host/render_frame_host_manager.cc b/content/browser/frame_host/render_frame_host_manager.cc
index e174e54d379ca834c1016b919b53d5325fb0ce0d..91a2a832bdc067d4b4e2f29aa06021c42c32fc5f 100644
--- a/content/browser/frame_host/render_frame_host_manager.cc
+++ b/content/browser/frame_host/render_frame_host_manager.cc
@@ -1401,12 +1401,13 @@ RenderFrameHostManager::DetermineSiteInstanceForURL(
                                   SiteInstanceRelation::UNRELATED);
   }
 
-  // Use the source SiteInstance in case of data URLs or about:blank pages,
-  // because the content is then controlled and/or scriptable by the source
-  // SiteInstance.
+  // Use the source SiteInstance in case of data URLs, about:srcdoc pages and
+  // about:blank pages because the content is then controlled and/or scriptable
+  // by the source SiteInstance.
   GURL about_blank(url::kAboutBlankURL);
-  if (source_instance &&
-      (dest_url == about_blank || dest_url.scheme() == url::kDataScheme)) {
+  GURL about_srcdoc(content::kAboutSrcDocURL);
+  if (source_instance && (dest_url == about_srcdoc || dest_url == about_blank ||

[Charlie Reis, 2016/11/11 22:53:24]

Good catch-- that seems right to me.  (I suppose there's a risk of regressing
other similar logic that we don't remember to fix, but maybe that's ok.)

[arthursonzogni, 2016/11/15 16:37:09]

FYI, this modification fixes the test:
FrameTreeBrowserTest.ChildFrameWithSrcdoc
with the --site-per-process flag.

I hope there won't be serious regression.
I tried to find other place where the same kind of modifications may apply, but
since there is no failing tests, it is harder to understand what should be done.

Probably here:
https://cs.chromium.org/chromium/src/chrome/browser/history/history_utils.cc?...

Maybe not here (it is on the renderer side):
https://cs.chromium.org/chromium/src/content/renderer/render_frame_impl.cc?cl...
https://cs.chromium.org/chromium/src/content/renderer/render_frame_impl.cc?cl...

[Charlie Reis, 2016/11/16 18:20:22]

I'm not sure if that ever gets called for subframes.  I suppose it wouldn't hurt
to add it, though, just in case.
Agreed that it shouldn't matter on the renderer side, since it never rewrote
about:srcdoc to about:blank in the first place (though apparently the code has
changed and those links don't appear to work).

Besides those, there's a chance that it's relevant to
SiteInstanceImpl::IsSameWebSite, but I think the change you're making here is
actually the right way to handle that one.

+                          dest_url.scheme() == url::kDataScheme)) {
     return SiteInstanceDescriptor(source_instance);
   }