Revert of Fix mojo_js_unittests (https://codereview.chromium.org/197463005/)

Reason for revert:
Suspected of breaking the build.
http://build.chromium.org/p/chromium.mac/buildstatus?builder=Mac10.6%20Tests%20%283%29&number=46233

[ RUN      ] JSTest.codec
../../gin/test/file_runner.cc:71: Failure
Value of: V8ToString(result)
  Actual: ""
Expected: "PASS"
[  FAILED  ] JSTest.codec (13 ms)
[2/2] JSTest.codec (13 ms)
Retrying 1 test (retry #1)
[ RUN      ] JSTest.codec
../../gin/test/file_runner.cc:71: Failure
Value of: V8ToString(result)
  Actual: ""
Expected: "PASS"
[  FAILED  ] JSTest.codec (16 ms)
[3/3] JSTest.codec (16 ms)
Retrying 1 test (retry #2)
[ RUN      ] JSTest.codec
../../gin/test/file_runner.cc:71: Failure
Value of: V8ToString(result)
  Actual: ""
Expected: "PASS"
[  FAILED  ] JSTest.codec (16 ms)
[4/4] JSTest.codec (16 ms)
Retrying 1 test (retry #3)
[ RUN      ] JSTest.codec
../../gin/test/file_runner.cc:71: Failure
Value of: V8ToString(result)
  Actual: ""
Expected: "PASS"
[  FAILED  ] JSTest.codec (16 ms)
[5/5] JSTest.codec (16 ms)
1 test failed:
    JSTest.codec
Tests took 0 seconds.


Original issue's description:
> Fix mojo_js_unittests
> 
> BUG=351214
> TEST=The test should succeed
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=256791

TBR=sky@chromium.org,yzshen@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=351214

Review URL: https://codereview.chromium.org/198193004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256804 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 256804