Restore SkPath(const SkPath&) to copy the generation ID on Android.

src/core/SkPath.cpp

Index: src/core/SkPath.cpp
diff --git a/src/core/SkPath.cpp b/src/core/SkPath.cpp
index 875be9801e4d2910c2a757652abbb1c4a32395d3..b119e88f939527a1fee1d1d24a6d3f8f7e5053b4 100644
--- a/src/core/SkPath.cpp
+++ b/src/core/SkPath.cpp
@@ -185,11 +185,7 @@ void SkPath::resetFields() {
 }
 
 SkPath::SkPath(const SkPath& that)
-    : fPathRef(SkRef(that.fPathRef.get()))
-#ifdef SK_BUILD_FOR_ANDROID
-    , fGenerationID(0)
-#endif
-{
+    : fPathRef(SkRef(that.fPathRef.get())) {
     this->copyFields(that);
     SkDEBUGCODE(that.validate();)
 }
@@ -221,8 +217,8 @@ void SkPath::copyFields(const SkPath& that) {
     fIsFinite        = that.fIsFinite;
     fIsOval          = that.fIsOval;
 #ifdef SK_BUILD_FOR_ANDROID
-    GEN_ID_INC;
-    fSourcePath      = NULL;
+    fGenerationID    = that.fGenerationID;

[bungeman-skia, 2013/08/06 20:09:48]

Similar situation to swap. Can't this make this object's generation ID go
backwards (for operator=)?

[mtklein, 2013/08/06 20:23:35]

Done.

+    fSourcePath      = NULL;  // TODO(mtklein): follow up with Android: do we want to copy this too?
 #endif
 }
 
@@ -253,8 +249,13 @@ void SkPath::swap(SkPath& that) {
         SkTSwap<uint8_t>(fDirection, that.fDirection);
         SkTSwap<SkBool8>(fIsFinite, that.fIsFinite);
         SkTSwap<SkBool8>(fIsOval, that.fIsOval);
+#ifdef SK_BUILD_FOR_ANDROID
+        // It doesn't really make sense to swap the generation IDs here, because they might go
+        // backwards.  To be safe we increment both to mark them both as changed.
         GEN_ID_INC;
         GEN_ID_PTR_INC(&that);
+        SkTSwap<SkPath*>(fSourcePath, that.fSourcePath);
+#endif
     }
 }