Revert 89453 - Support automatic javascript test registry in gtest when creating WebUI tests.

Revert 89453 - Support automatic javascript test registry in gtest when creating WebUI tests.
- gypv8sh.py is breaking on Mac
http://build.chromium.org/p/chromium/builders/Mac10.5%20Tests%20%281%29/builds/8563/steps/update/logs/stdio
  File "/b/build/slave/Mac10_5_Tests__1_/build/src/tools/gyp/pylib/gyp/input.py", line 1017, in ProcessVariablesAndConditionsInList
    expanded = ExpandVariables(item, is_late, variables, build_file)
  File "/b/build/slave/Mac10_5_Tests__1_/build/src/tools/gyp/pylib/gyp/input.py", line 684, in ExpandVariables
    (contents, p.returncode))
Exception: Call to 'python ../tools/gypv8sh.py -i' returned exit status 1. while loading dependencies of src/chrome/browser/sync/tools/sync_tools.gyp while loading dependencies of src/build/all.gyp while trying to load src/build/all.gyp
Error: /System/Library/Frameworks/Python.framework/Versions/2.5/Resources/Python.app/Contents/MacOS/Python src/build/gyp_chromium in /b/build/slave/Mac10_5_Tests__1_/build returned 1


The goal was to support something as simple as the following, where the tests in the
javascript files would be 1st class GTESTs, supporting FLAKY_, DISABLED_, etc, and
registered at linker_initialization time.

WEB_UI_BROWSER_TEST_JS(WebUIBrowserTest, TestJSPass,
                       FILE_PATH_LITERAL("sample_passing.js")) {
  ui_test_utils::NavigateToURL(browser(), GURL(chrome::kChromeUIDownloadsURL));
}

WEB_UI_BROWSER_TEST_JS_FALSE(WebUIBrowserTest, TestJSFail,
                             FILE_PATH_LITERAL("sample_failing.js")) {
  ui_test_utils::NavigateToURL(browser(), GURL(chrome::kChromeUIDownloadsURL));
}

http://www.chromium.org/Home/domui-testing

In order to support linker init time, I had to modify path_service to support
Unregistration, and chrome_paths to allow multiple invocations.

BUG=82437
R=estade@chromium.org,jhawkins@chromium.org
TEST=browser_tests --gtest_filter=WebUIBrowserTest*


Review URL: http://codereview.chromium.org/7087014

TBR=scr@chromium.org
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=89460