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, 7 insertions, 1 deletions

diff --git a/src/core/SkPictureFlat.h b/src/core/SkPictureFlat.h
index ed9d0684fd..448e9d5537 100644
--- a/src/core/SkPictureFlat.h
+++ b/src/core/SkPictureFlat.h
@@ -96,8 +96,10 @@ enum DrawType {
     DRAW_VERTICES_OBJECT,
 
     FLUSH,
+    SAVE_BEHIND,
+    DRAW_BEHIND_PAINT,
 
-    LAST_DRAWTYPE_ENUM = FLUSH
+    LAST_DRAWTYPE_ENUM = DRAW_BEHIND_PAINT,
 };
 
 // In the 'match' method, this constant will match any flavor of DRAW_BITMAP*
@@ -128,6 +130,10 @@ enum SaveLayerRecFlatFlags {
     SAVELAYERREC_HAS_CLIPMATRIX = 1 << 5,
 };
 
+enum SaveBehindFlatFlags {
+    SAVEBEHIND_HAS_SUBSET = 1 << 0,
+};
+
 ///////////////////////////////////////////////////////////////////////////////
 // clipparams are packed in 5 bits
 //  doAA:1 | clipOp:4