consolidate SaveLayerFlag internal references

Add a third define in SkCanvasPriv to complement
SkCanvas::kDontClipToLayer_PrivateSaveLayerFlag and
SkCanvas::kDontClipToLayer_Legacy_SaveLayerFlag.

SkCanvas::kDontClipToLayer_PrivateSaveLayerFlag exists only to define
SkCanvas::kDontClipToLayer_Legacy_SaveLayerFlag and
SkCanvasPriv::kDontClipToLayer_SaveLayerFlag.

SkCanvas::kDontClipToLayer_Legacy_SaveLayerFlag is used only by
Android framework.

SkCanvasPriv::kDontClipToLayer_SaveLayerFlag is used internally.

Note that changes to CanvasStateTest.cpp inside
SK_SUPPORT_LEGACY_CLIPTOLAYERFLAG aren't testable by existing
skiabots; it requires building an Android framework aware version
of dm. CanvasStateTest.cpp may have bit-rotted.

R=reed@google.com,scroggo@google.com
Bug: skia:6454,skia:7690
Change-Id: I74f2a54636fae89a5a88a7e13f1baba49d3e2115
Reviewed-on: https://skia-review.googlesource.com/112401
Commit-Queue: Cary Clark <caryclark@skia.org>
Reviewed-by: Leon Scroggins <scroggo@google.com>
Reviewed-by: Mike Reed <reed@google.com>
10 files changed