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, 18 insertions, 0 deletions

diff --git a/src/core/SkPicturePlayback.cpp b/src/core/SkPicturePlayback.cpp
index 7b9e411764..e2159bead9 100644
--- a/src/core/SkPicturePlayback.cpp
+++ b/src/core/SkPicturePlayback.cpp
@@ -419,6 +419,14 @@ void SkPicturePlayback::handleOp(SkReadBuffer* reader,
                 canvas->drawPaint(*paint);
             }
         } break;
+        case DRAW_BEHIND_PAINT: {
+            const SkPaint* paint = fPictureData->getPaint(reader);
+            BREAK_ON_READ_ERROR(reader);
+
+            if (paint) {
+                SkCanvasPriv::DrawBehind(canvas, *paint);
+            }
+        } break;
         case DRAW_PATCH: {
             const SkPaint* paint = fPictureData->getPaint(reader);
 
@@ -685,6 +693,16 @@ void SkPicturePlayback::handleOp(SkReadBuffer* reader,
         case SAVE:
             canvas->save();
             break;
+        case SAVE_BEHIND: {
+            uint32_t flags = reader->readInt();
+            const SkRect* subset = nullptr;
+            SkRect storage;
+            if (flags & SAVEBEHIND_HAS_SUBSET) {
+                reader->readRect(&storage);
+                subset = &storage;
+            }
+            SkCanvasPriv::SaveBehind(canvas, subset);
+        } break;
         case SAVE_LAYER_SAVEFLAGS_DEPRECATED: {
             SkRect storage;
             const SkRect* boundsPtr = get_rect_ptr(reader, &storage);