Show hosted app requests to extensions

BUG=526413
TEST=browser_tests --gtest_filter=ExtensionWebRequestApiTest.HostedAppRequest

Review URL: https://codereview.chromium.org/1311543005

Cr-Commit-Position: refs/heads/master@{#347756}
(cherry picked from commit 1db473b2e3b66646a7470e543540a44e854cd8f7)

Review URL: https://codereview.chromium.org/1336933002 .

Cr-Commit-Position: refs/branch-heads/2454@{#461}
Cr-Branched-From: 12bfc3360892ec53cd00fc239a47e5298beb063b-refs/heads/master@{#338390}
5 files changed