Initial error handling code

src/effects/SkArithmeticMode.cpp

Index: src/effects/SkArithmeticMode.cpp
diff --git a/src/effects/SkArithmeticMode.cpp b/src/effects/SkArithmeticMode.cpp
index fd3a683fbb92bc009c12daa290366da6724bf210..23f50faa51eec822317b45f43e8d229fcf808493 100644
--- a/src/effects/SkArithmeticMode.cpp
+++ b/src/effects/SkArithmeticMode.cpp
@@ -231,6 +231,25 @@ SkXfermode* SkArithmeticMode::Create(SkScalar k1, SkScalar k2,
     return SkNEW_ARGS(SkArithmeticMode_scalar, (k1, k2, k3, k4));
 }
 
+SkFlattenable::Factory SkArithmeticMode::GetFactory(SkFlattenable::Type type) {
+    switch(type) {

[mtklein, 2013/09/24 22:52:18]

For these small guys, I think you're going to be leaving folks scratching their
heads why you didn't write

if (SkFlattenable::kSkArithmeticMode_scalar == type) {
  return SkArithmeticMode_scalar::CreateProc;
}
return NULL;

Similar below and I'm guessing on many files to come.

[sugoi1, 2013/09/25 21:15:27]

Done.

+    case SkFlattenable::kSkArithmeticMode_scalar:
+        return SkArithmeticMode_scalar::CreateProc;
+    default:
+        break;
+    }
+    return NULL;
+}
+
+SkFlattenable::TypeCheck SkArithmeticMode::GetTypeCheck(SkFlattenable::Type type) {
+    switch(type) {
+    case SkFlattenable::kSkArithmeticMode_scalar:
+        return SkArithmeticMode_scalar::IsA;
+    default:
+        break;
+    }
+    return NULL;
+}
 
 //////////////////////////////////////////////////////////////////////////////