Fix ClipMaskManager's SW-fallback logic

'useSWOnlyPath' was not correctly toggling between stencil and color draws so there was a mismatch with the behavior in createAlphaClipMask (i.e., we were inadvertently rendering some of the elements in a clip using SW but using stenciling for others - precisely what 'useSWOnlyPath' was intended to prevent).

Review URL: https://codereview.chromium.org/1421533007
7 files changed