Revert of Be explicit about forcing TouchSelectionController updates

Revert of Be explicit about forcing TouchSelectionController updates (patchset #2 id:20001 of https://codereview.chromium.org/1127383007/)

Reason for revert:
This has caused failures on the memory bots. e.g.:http://build.chromium.org/p/chromium.memory.fyi/builders/Linux%20MSan%20Tests/builds/6179

Sample test output:
[ RUN      ] TouchSelectionControllerTest.AllowShowingFromCurrentSelection
==6485== WARNING: MemorySanitizer: use-of-uninitialized-value
    #0 0x7f5bc93bb605 in ui::TouchSelectionController::OnSelectionBoundsChanged(ui::SelectionBound const&, ui::SelectionBound const&) ui/touch_selection/touch_selection_controller.cc:71:27
    #1 0x7f5bc922803a in ui::TouchSelectionControllerTest::ChangeSelection(gfx::RectF const&, bool, gfx::RectF const&, bool) ui/touch_selection/touch_selection_controller_unittest.cc:147:5
    #2 0x7f5bc9278c8d in ui::TouchSelectionControllerTest_AllowShowingFromCurrentSelection_Test::TestBody() ui/touch_selection/touch_selection_controller_unittest.cc:946:3
    #3 0x7f5bc93631dc in HandleExceptionsInMethodIfSupported\u003Ctesting::Test, void> testing/gtest/src/gtest.cc:2420:12
    #4 0x7f5bc93631dc in testing::Test::Run() testing/gtest/src/gtest.cc:2436:0
    #5 0x7f5bc9365a4c in testing::TestInfo::Run() testing/gtest/src/gtest.cc:2612:5
    #6 0x7f5bc93673f6 in testing::TestCase::Run() testing/gtest/src/gtest.cc:2730:5
    #7 0x7f5bc9384d03 in testing::internal::UnitTestImpl::RunAllTests() testing/gtest/src/gtest.cc:4602:11
    #8 0x7f5bc9383ce2 in HandleExceptionsInMethodIfSupported\u003Ctesting::internal::UnitTestImpl, bool> testing/gtest/src/gtest.cc:2420:12
    #9 0x7f5bc9383ce2 in testing::UnitTest::Run() testing/gtest/src/gtest.cc:4220:0
    #10 0x7f5bc93078a3 in RUN_ALL_TESTS testing/gtest/include/gtest/gtest.h:2326:10
    #11 0x7f5bc93078a3 in base::TestSuite::Run() base/test/test_suite.cc:228:0
    #12 0x7f5bc92f7b2d in (anonymous namespace)::RunTestSuite(int, char**) base/test/run_all_unittests.cc:25:10
    #13 0x7f5bc92f85ee in Run base/callback.h:396:12
    #14 0x7f5bc92f85ee in base::(anonymous namespace)::LaunchUnitTestsInternal(base::Callback\u003Cint ()> const&, int, bool, base::Callback\u003Cvoid ()> const&) base/test/launcher/unit_test_launcher.cc:184:0
    #15 0x7f5bc92f7f5b in base::LaunchUnitTests(int, char**, base::Callback\u003Cint ()> const&) base/test/launcher/unit_test_launcher.cc:423:10
    #16 0x7f5bc92f792d in main base/test/run_all_unittests.cc:37:10
    #17 0x7f5bc206a76c in __libc_start_main /build/buildd/eglibc-2.15/csu/libc-start.c:226:0
    #18 0x7f5bc9188f38 in _start ??:0:0

  Uninitialized value was created by a heap allocation
    #0 0x7f5bc91da0e2 in operator new(unsigned long) ??:0:0
    #1 0x7f5bc927c95c in ui::TouchSelectionControllerTest::SetUp() ui/touch_selection/touch_selection_controller_unittest.cc:65:23
    #2 0x7f5bc9362f57 in HandleExceptionsInMethodIfSupported\u003Ctesting::Test, void> testing/gtest/src/gtest.cc:2420:12
    #3 0x7f5bc9362f57 in testing::Test::Run() testing/gtest/src/gtest.cc:2432:0
    #4 0x7f5bc9365a4c in testing::TestInfo::Run() testing/gtest/src/gtest.cc:2612:5
    #5 0x7f5bc93673f6 in testing::TestCase::Run() testing/gtest/src/gtest.cc:2730:5
    #6 0x7f5bc9384d03 in testing::internal::UnitTestImpl::RunAllTests() testing/gtest/src/gtest.cc:4602:11
    #7 0x7f5bc9383ce2 in HandleExceptionsInMethodIfSupported\u003Ctesting::internal::UnitTestImpl, bool> testing/gtest/src/gtest.cc:2420:12
    #8 0x7f5bc9383ce2 in testing::UnitTest::Run() testing/gtest/src/gtest.cc:4220:0
    #9 0x7f5bc93078a3 in RUN_ALL_TESTS testing/gtest/include/gtest/gtest.h:2326:10
    #10 0x7f5bc93078a3 in base::TestSuite::Run() base/test/test_suite.cc:228:0
    #11 0x7f5bc92f7b2d in (anonymous namespace)::RunTestSuite(int, char**) base/test/run_all_unittests.cc:25:10
    #12 0x7f5bc92f85ee in Run base/callback.h:396:12
    #13 0x7f5bc92f85ee in base::(anonymous namespace)::LaunchUnitTestsInternal(base::Callback\u003Cint ()> const&, int, bool, base::Callback\u003Cvoid ()> const&) base/test/launcher/unit_test_launcher.cc:184:0
    #14 0x7f5bc92f7f5b in base::LaunchUnitTests(int, char**, base::Callback\u003Cint ()> const&) base/test/launcher/unit_test_launcher.cc:423:10
    #15 0x7f5bc92f792d in main base/test/run_all_unittests.cc:37:10
    #16 0x7f5bc206a76c in __libc_start_main /build/buildd/eglibc-2.15/csu/libc-start.c:226:0

SUMMARY: MemorySanitizer: use-of-uninitialized-value (/mnt/data/b/build/slave/Linux_MSan_Tests/build/src/out/Release/ui_touch_selection_unittests+0x285605)
Exiting

Original issue's description:
> Be explicit about forcing TouchSelectionController updates
>
> Previously, cached values in the TouchSelectionController would be reset
> to force future selection updates. However, these cached values can
> actually be used outside of selection update calls, e.g., when force
> showing the selection from the current cached values. Instead of
> resetting the cached values, simply set a dirty bit that forces an
> update, avoiding issues when dealing with the reset values.
>
> BUG=393025
>
> Committed: https://crrev.com/fdcf817da49ee92fe191981f7525503444f75f83
> Cr-Commit-Position: refs/heads/master@{#329325}

TBR=mohsen@chromium.org,jdduke@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=393025
Committed: https://crrev.com/e63eab6ae8072fc359f151e245e07d4864035ba2
Cr-Commit-Position: refs/heads/master@{#329352}

[benwells, 2015-05-12 04:51:18]

Created Revert of Be explicit about forcing TouchSelectionController updates

[commit-bot: I haz the power, 2015-05-12 04:51:57]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1139533006/1

[commit-bot: I haz the power, 2015-05-12 04:52:59]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-05-12 04:53:45]

Patchset 1 (id:??) landed as
https://crrev.com/e63eab6ae8072fc359f151e245e07d4864035ba2
Cr-Commit-Position: refs/heads/master@{#329352}