Revert "[CSS Blending] Implement mix-blend-mode in software."

> [CSS Blending] Implement mix-blend-mode in software.
> The implementation follows the CSS Blending and compositing
> spec at http://dev.w3.org/fxtf/compositing-1/
>
> It seems that there might be slightly better performance if we use the software path for CSS blending. Basically, on the hardware path, there are some bitmap copy operations involved, and we'd like to avoid this whenever possible.
>
> The hardware implementation, currently in the works will only be followed for elements that force the creation of a composited layer.
>
> BUG=288655
>
> Review URL: https://codereview.chromium.org/23503046

TBR=mitica@adobe.com

Review URL: https://codereview.chromium.org/27198002

git-svn-id: svn://svn.chromium.org/blink/trunk@159585 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Delete all CPU profiles and heap snapshots on front-end disconnection

* Profiler data is not preserved between front-end sessions anymore.
* {Heap}Profiler.getProfileHeaders commands were removed from the protocol. HeapProfiler.enable/disable were added to control events being sent to front-end.

BUG=306375
R=loislo@chromium.org

Review URL: https://codereview.chromium.org/26807005

git-svn-id: svn://svn.chromium.org/blink/trunk@159586 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove Backslash-as-JPY hack

We should not go to extra length to emulate 'the broken' behavior of Windows
Japanese fonts on non-Windows platforms.

BUG=305827
TEST=Layout test (related tests are removed).

Review URL: https://codereview.chromium.org/27030014

git-svn-id: svn://svn.chromium.org/blink/trunk@159589 bbb929c8-8fbe-4397-9dbb-9b2b20218538