Instant Apps: Add instrumentation tests.

Adds some of the missing tests for instant apps.

Committed: https://crrev.com/916f90ce1912767f926d0389f988f49e8b1799c2
Cr-Commit-Position: refs/heads/master@{#439604}

I just merged something that will probably break the branch because it uses some constants in the tests that were introduced in this CL. Requesting merge of the tests to unbreak the branch.

This request is to fix the merge in crbug.com/675757

Proposed fix is in https://codereview.chromium.org/2593093002/

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b7e00b43872a25473a2e785119673c67cc0849ff

commit b7e00b43872a25473a2e785119673c67cc0849ff
Author: Maria Khomenko <mariakhomenko@chromium.org>
Date: Wed Dec 21 18:32:39 2016

Instant Apps: Add instrumentation tests.

Adds some of the missing tests for instant apps.

BUG= 676369 ,675757

Review-Url: https://codereview.chromium.org/2550413007
Cr-Commit-Position: refs/heads/master@{#439604}
(cherry picked from commit 916f90ce1912767f926d0389f988f49e8b1799c2)

R=dfalcantara@chromium.org

Review-Url: https://codereview.chromium.org/2593093002 .
Cr-Commit-Position: refs/branch-heads/2924@{#580}
Cr-Branched-From: 3a87aecc31cd1ffe751dd72c04e5a96a1fc8108a-refs/heads/master@{#433059}

[modify] https://crrev.com/b7e00b43872a25473a2e785119673c67cc0849ff/chrome/android/javatests/src/org/chromium/chrome/browser/externalnav/ExternalNavigationHandlerTest.java
[modify] https://crrev.com/b7e00b43872a25473a2e785119673c67cc0849ff/chrome/android/javatests/src/org/chromium/chrome/browser/instantapps/InstantAppsHandlerTest.java

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/05739547aca189e6bf24e2e14c56eb9810420792

commit 05739547aca189e6bf24e2e14c56eb9810420792
Author: Maria Khomenko <mariakhomenko@chromium.org>
Date: Wed Dec 21 19:11:11 2016

Instant Apps: Add instrumentation tests.

Adds some of the missing tests for instant apps.

R=dfalcantara@chromium.org
BUG= 676369 ,675757

Review-Url: https://codereview.chromium.org/2550413007
Cr-Commit-Position:refs/heads/master@{#439604}
(cherry picked from commit 916f90ce1912767f926d0389f988f49e8b1799c2)

Review-Url: https://codereview.chromium.org/2599513002 .
Cr-Commit-Position: refs/branch-heads/2924@{#583}
Cr-Branched-From: 3a87aecc31cd1ffe751dd72c04e5a96a1fc8108a-refs/heads/master@{#433059}

[modify] https://crrev.com/05739547aca189e6bf24e2e14c56eb9810420792/chrome/android/javatests/src/org/chromium/chrome/browser/externalnav/ExternalNavigationHandlerTest.java