Add private save-behind and draw-behind methods to canvas.HEADp9.0

The draw-behind  is a variant of drawPaint but is automatically clipped
to the bounds of the most recent saveBehind buffer (axis-aligned bounds).

No public exposure outside of the Android framework.

Impl is pretty simple (its a variant of drawPaint)
- find the most recent saveBehind device bounds
- if there is none, draw nothing, else
  - temporarily intersect the device's clip with that bounds
  - drawPaint
  - restore the clip

This patches did not apply cleanly and have been updated to compile
with a previous version of Skia. It was cherry-picked from the
following 3 Skia commits:
148b7fd3ad9c29dec0052de624c26ff291ef8f0a
d567408362bf7847d6000f6786f9a7b2c9d0b88b
9adc82c73df0ef25b708cae8aa48ef9c39ed4c67

Bug: 129117085
Test: None
Change-Id: I291f57885de6e95f749bf5cdb70ac16a5781ffb1

1 files changed, 2 insertions, 0 deletions

diff --git a/src/core/SkLiteDL.h b/src/core/SkLiteDL.h
index 6d63657084..ff0fcb796d 100644
--- a/src/core/SkLiteDL.h
+++ b/src/core/SkLiteDL.h
@@ -34,6 +34,7 @@ public:
     void save();
     void saveLayer(const SkRect*, const SkPaint*, const SkImageFilter*, const SkImage*,
                    const SkMatrix*, SkCanvas::SaveLayerFlags);
+    void saveBehind(const SkRect*);
     void restore();
 
     void    concat (const SkMatrix&);
@@ -47,6 +48,7 @@ public:
     void clipRegion(const SkRegion&, SkClipOp);
 
     void drawPaint (const SkPaint&);
+    void drawBehind(const SkPaint&);
     void drawPath  (const SkPath&, const SkPaint&);
     void drawRect  (const SkRect&, const SkPaint&);
     void drawRegion(const SkRegion&, const SkPaint&);