Revert of Use labels to display views tab titles.

Revert of Use labels to display views tab titles. (https://codereview.chromium.org/323993002/)

Reason for revert:
Appears to have a memory leak. See:

http://build.chromium.org/p/chromium.memory/builders/Linux%20ASan%20LSan%20Tests%20%283%29/builds/3954

Original issue's description:
> Use labels to display views tab titles.
> 
> Add a Label view to Tab for displaying the title.
> Remove Tab::PaintTitle, bounds and font members.
> Remove unnecessary Tab::Get[Title|Icon]Bounds helpers.
> Update the text on Tab::SetData, not during paint.
> Use gfx::DirectionalityMode, remove the Label enum.
> 
> Add gfx::ALIGN_TO_HEAD to gfx::HorizontalAlignment.
> Add Label::GetHorizontalAlignment for ALIGN_TO_HEAD.
> Always flip left/right in Label::SetHorizontalAlignment.
> Have Tab and MessageBoxView use ALIGN_TO_HEAD.
> 
> Update comments and tests, related minor cleanup.
> 
> TODO: Make Label cache RenderText objects.
> TODO: Make RenderText support ALIGN_TO_HEAD.
> 
> BUG=240037
> TEST=No visible Views tab title changes.
> R=sky@chromium.org
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=276450

TBR=sky@chromium.org,msw@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=240037
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=276476

[please use gerrit instead, 2014-06-11 19:27:46]

Created Revert of Use labels to display views tab titles.

[commit-bot: I haz the power, 2014-06-11 19:28:50]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/rouslan@chromium.org/327273005/1

[commit-bot: I haz the power, 2014-06-11 19:33:56]

Change committed as 276476

[msw, 2014-06-11 19:57:47]

lgtm, ty.