Initial clip-mask-layer support

SkBitmapDevice-only implementation.

Will add A8 fast path specializations in a follow-up.

Change-Id: I2ccb1ffba3689e92ac90a23e94737471dfb121a1
BUG=skia:6005

Change-Id: I2ccb1ffba3689e92ac90a23e94737471dfb121a1
Reviewed-on: https://skia-review.googlesource.com/14183
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Florin Malita <fmalita@chromium.org>
diff --git a/src/core/SkRecorder.cpp b/src/core/SkRecorder.cpp
index 0f2891a..c9d88fc 100644
--- a/src/core/SkRecorder.cpp
+++ b/src/core/SkRecorder.cpp
@@ -366,6 +366,8 @@
     APPEND(SaveLayer, this->copy(rec.fBounds)
                     , this->copy(rec.fPaint)
                     , sk_ref_sp(rec.fBackdrop)
+                    , rec.fClipMask
+                    , this->copy(rec.fClipMatrix)
                     , rec.fSaveLayerFlags);
     return SkCanvas::kNoLayer_SaveLayerStrategy;
 }