Fix recording of saveLayout with unusual Xfermodes.

src/core/SkRecordDraw.cpp

Index: src/core/SkRecordDraw.cpp
diff --git a/src/core/SkRecordDraw.cpp b/src/core/SkRecordDraw.cpp
index ac1e429f1227a575e27cb0342171842ac46a41b7..983752aeda9ea3821d9f9e7555f9e1d7247581dd 100644
--- a/src/core/SkRecordDraw.cpp
+++ b/src/core/SkRecordDraw.cpp
@@ -229,8 +229,33 @@ private:
     }
 
     static bool PaintMayAffectTransparentBlack(const SkPaint* paint) {
-        // FIXME: this is very conservative
-        return paint && (paint->getImageFilter() || paint->getColorFilter());
+        if (paint) {
+            // FIXME: this is very conservative
+            if (paint->getImageFilter() || paint->getColorFilter())

[mtklein, 2014/09/12 19:20:08]

Please add {} 

[dneto, 2014/09/12 20:41:42]

Done.

+                return true;
+
+            SkXfermode* xfermode = paint->getXfermode();

[dneto, 2014/09/12 18:23:03]

This codepath is not the default for Chromium, but it is the default for Skia
when its own tree.

[mtklein, 2014/09/12 19:20:08]

Sync up!  :P

[dneto, 2014/09/12 20:41:42]

Acknowledged.
Yeah, that's outta my control.  I tested with both paths, which was fun. :-)

+            SkXfermode::Mode mode;
+            // SrcOver is ok, and is also the common case with a NULL xfermode.
+            // So we should make that the fast path and bypass the mode extraction
+            // and test.
+            if (xfermode && xfermode->asMode(&mode)) {
+                switch (mode) {
+                    case SkXfermode::kClear_Mode:
+                    case SkXfermode::kSrc_Mode:
+                    case SkXfermode::kSrcIn_Mode:
+                    case SkXfermode::kDstIn_Mode:
+                    case SkXfermode::kSrcOut_Mode:
+                    case SkXfermode::kDstATop_Mode:
+                    case SkXfermode::kModulate_Mode:
+                        return true;
+                        break;
+                    default:
+                        break;
+                }
+            }
+        }
+        return false;
     }
 
     Bounds popSaveBlock() {