Revert 256563 "Reland r256396 Add views implementation for AXTre..."

Turned the chromeos lsan bot red:

Indirect leak of 48 byte(s) in 1 object(s) allocated from:
    #0 0x480201 in operator new(unsigned long) /usr/local/google/work/chromium/src/third_party/llvm/projects/compiler-rt/lib/asan/asan_new_delete.cc:54
    #1 0x49e263 in ui::AXTreeSerializer\u003Cviews::View*>::SerializeChangedNodes(views::View*, ui::AXTreeUpdate*) ui/accessibility/ax_tree_serializer.h:372
    #2 0x49b75a in ui::AXTreeSerializer\u003Cviews::View*>::SerializeChanges(views::View*, ui::AXTreeUpdate*) ui/accessibility/ax_tree_serializer.h:329
    #3 0x49992d in views::AXTreeSourceViewsTest_SimpleSerialization_Test::TestBody() ui/views/accessibility/ax_tree_source_views_unittest.cc:75
    #4 0xb859ba in HandleExceptionsInMethodIfSupported\u003Ctesting::Test, void> testing/gtest/src/gtest.cc:2045
    #5 0xb859ba in testing::Test::Run() testing/gtest/src/gtest.cc:2061
    #6 0xb874c9 in testing::TestInfo::Run() testing/gtest/src/gtest.cc:2237
    #7 0xb88243 in testing::TestCase::Run() testing/gtest/src/gtest.cc:2344
    #8 0xb98e9a in testing::internal::UnitTestImpl::RunAllTests() testing/gtest/src/gtest.cc:4065
    #9 0xb984a0 in HandleExceptionsInMethodIfSupported\u003Ctesting::internal::UnitTestImpl, bool> testing/gtest/src/gtest.cc:2045
    #10 0xb984a0 in testing::UnitTest::Run() testing/gtest/src/gtest.cc:3697
    #11 0xb51664 in RUN_ALL_TESTS testing/gtest/include/gtest/gtest.h:2231
    #12 0xb51664 in base::TestSuite::Run() base/test/test_suite.cc:213
    #13 0xb47d1d in Run base/callback.h:401
    #14 0xb47d1d in base::(anonymous namespace)::LaunchUnitTestsInternal(int, char**, base::Callback\u003Cint ()> const&, int) base/test/launcher/unit_test_launcher.cc:494
    #15 0x80bdba in main ui/views/run_all_unittests.cc:46
    #16 0x7f0caf06376c in __libc_start_main /build/buildd/eglibc-2.15/csu/libc-start.c:226

http://build.chromium.org/p/chromium.memory/builders/Linux%20Chromium%20OS%20ASan%2BLSan%20Tests%20%281%29/builds/222/steps/views_unittests/logs/SimpleSerialization

> Reland r256396 Add views implementation for AXTreeSource.
> 
> BUG=318758
> TBR=dtseng@chromium.org
> 
> Review URL: https://codereview.chromium.org/196603003

TBR=dtseng@google.com

Review URL: https://codereview.chromium.org/196953009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256745 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 256745