[ios] Moves GetContentAndFragmentForUrl() into ios/net.

For EG2 tests, we'd like to use ios/web/public/test/http_server from the
test process, but without pulling in all of //ios/web.  Moving this
utility function allows http_server to depend only on //base, //net, and
//url.

BUG=930859

Change-Id: Ia1e35b04089a3bd2cf00ee0e7a663783ac2762a7
Reviewed-on: https://chromium-review.googlesource.com/c/1473616
Reviewed-by: Eugene But <eugenebut@chromium.org>
Commit-Queue: Rohit Rao <rohitrao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#632352}

diff --git a/ios/net/BUILD.gn b/ios/net/BUILD.gn
index bed74bbc..0861b62 100644
--- a/ios/net/BUILD.gn
+++ b/ios/net/BUILD.gn

@@ -94,6 +94,8 @@
     "cookies/cookie_store_ios_test_util.h",
     "cookies/cookie_store_ios_test_util.mm",
     "cookies/system_cookie_store_unittest_template.h",
+    "url_test_util.cc",
+    "url_test_util.h",
   ]
 }