[ios] Do not commit invalid URLs during web load.

BUG=622183

Review-Url: https://codereview.chromium.org/2086333003
Cr-Commit-Position: refs/heads/master@{#401761}
(cherry picked from commit c2d2b0f2f74dad0bdef196cf1657f0d584cbe3a7)

Review URL: https://codereview.chromium.org/2096023002 .

Cr-Commit-Position: refs/branch-heads/2743@{#467}
Cr-Branched-From: 2b3ae3b8090361f8af5a611712fc1a5ab2de53cb-refs/heads/master@{#394939}
1 file changed