Revert of Blink does not respect input.selectionStart and input.selectionEnd for some cases

Revert of Blink does not respect input.selectionStart and input.selectionEnd for some cases (https://codereview.chromium.org/258063005/)

Reason for revert:

Suspected of breaking browser_tests on various platforms:
* ClearPreviewWithAutofilledUsernameAndPassword
* ClearPreviewWithUsernameAutofilled
* PreviewSuggestionSelectionRange

[PasswordAutofillAgentTest.ClearPreviewWithUsernameAutofilled]
* Value of: username_element_.selectionStart()
* Actual: 0 (expected: |start|, which is: 3)

Logs are available here:
* http://build.chromium.org/p/chromium.webkit/builders/Linux%20Tests%20%28dbg%29/builds/3108/steps/browser_tests/logs/stdio

NOTRY=true
TBR=tkent

Original issue's description:
> Blink does not respect input.selectionStart and input.selectionEnd for some cases
> 
> Blink does not respect the input.selectionStart and input.selectionEnd. When
> input.selectionStart and input.selectionEnd is set and then value is set the blink
> always shows the selection with caret at end of text. This patch removes this
> bug by caching the selectionStart and selectionEnd in m_cachedSelectionStart
> and m_cachedSelectionEnd and checking the cached selection while setting
> input value.
> 
> This patch also removes the bug specifying that caret poistion is incompatible after updating value
> IDL attribute of unfocused INPUT element. When the value IDL attribute is updated of unfocused 
> INPUT element the caret moves at the end but other browser move the caret at the beginning of the value.
> The other browsers move the caret to the end of the value only if the INPUT is focused. 
> This patch removes this bug too.
> 
> BUG=367736, 133242
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=177651

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=177668

[Peter Beverloo, 2014-07-08 13:17:21]

Created Revert of Blink does not respect input.selectionStart and
input.selectionEnd for some cases

[commit-bot: I haz the power, 2014-07-08 13:18:51]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/peter@chromium.org/374883004/1

[commit-bot: I haz the power, 2014-07-08 13:18:51]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-07-08 13:18:52]

No LGTM from a valid reviewer yet. Only full committers are accepted.
Even if an LGTM may have been provided, it was from a non-committer or
a provisional committer, _not_ a full super star committer.
See http://www.chromium.org/getting-involved/become-a-committer
Note that this has nothing to do with OWNERS files.

[Peter Beverloo, 2014-07-08 13:20:09]

On 2014/07/08 13:18:52, I haz the power (commit-bot) wrote:
> No LGTM from a valid reviewer yet. Only full committers are accepted.
> Even if an LGTM may have been provided, it was from a non-committer or
> a provisional committer, _not_ a full super star committer.
> See http://www.chromium.org/getting-involved/become-a-committer
> Note that this has nothing to do with OWNERS files.

Very useful. TBR'd on tkent.

[Peter Beverloo, 2014-07-08 13:20:16]

The CQ bit was checked by peter@chromium.org

[commit-bot: I haz the power, 2014-07-08 13:21:29]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/peter@chromium.org/374883004/1

[Peter Beverloo, 2014-07-08 13:22:10]

The CQ bit was unchecked by peter@chromium.org

[Peter Beverloo, 2014-07-08 13:22:15]

The CQ bit was checked by peter@chromium.org

[commit-bot: I haz the power, 2014-07-08 13:22:16]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/peter@chromium.org/374883004/1

[commit-bot: I haz the power, 2014-07-08 13:23:03]

Change committed as 177668