import changes from tenfourfox-history:

- #469: expose adblock pref in UI (3c7ba565e) (partly)
- #483: speculative GC/CC retuning (851222ca4)
- enable intel atomic operations (8fba598e8)
- #482: better bidi M1358275 M1392181 M1428774 + backbugs (e88a717ab)
- #482: note to self (d70096a7c)
- #483: wrong way on purple buffer (otherwise OOMs result) (d1ee9ade1)
- #478 chemspill: M1446062 fixes M1446068 (d2a1328e6)
- #469: more hosts for adblock (d8ada86ef)
- M1252374 reduce mallocs in displayList generation (78a7470f6)
- #485: mostly working destructuring nested rest assignment (2edc0af3d)
- closes #486: amp up hashtables M1352889 M1352890 M1379282 (1a6015752)
- #469: more hosts and a miner for basic adblock (3b1a55df8)
- #405: fix idl (1dab98d2e)
- #469, #399: more adblock hosts, faster StringBegins/End, any-link, base/srcdoc M1247359 M843579 M1238804 (610226ea6)
- #334, closes #489: enable TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 for amtrak.com (595021326)
- #399: remove padding-box support M1166728 (845e1834f)
- #399: disable SPDY/3.1 M1287132 (540f47f9c)
- #488: basic support for DOM iterables, {NodeList,DOMTokenList}.forEach M1216751 M1290636 (8409d1511)
- closes #488: M1257849 M1244328 finish DOMTokenList transition, bustage fixes (6b1b6131e)
- #491: update certs and pins (d2003d9a6)
- closes #492: rc4 bad, increase throttle, update UAs, reduce font URL overhead, nerdwallet ATSUI font block (8f7a0cce0)
- #469: some more hosts for adblock (c1af11d1a)

dom/html/HTMLSharedElement.cpp

@@ -164,14 +164,15 @@ SetBaseURIUsingFirstBaseWithHref(nsIDocument* aDocument, nsIContent* aMustMatch)
         return;
       }
 
-      // Resolve the <base> element's href relative to our document URI
+      // Resolve the <base> element's href relative to our document's
+      // fallback base URI.
       nsAutoString href;
       child->GetAttr(kNameSpaceID_None, nsGkAtoms::href, href);
 
       nsCOMPtr<nsIURI> newBaseURI;
       nsContentUtils::NewURIWithDocumentCharset(
         getter_AddRefs(newBaseURI), href, aDocument,
-        aDocument->GetDocumentURI());
+        aDocument->GetFallbackBaseURI());
 
       // Try to set our base URI.  If that fails, try to set base URI to null
       nsresult rv = aDocument->SetBaseURI(newBaseURI);