Added toString to SkXfermode-derived classes (for debugger) 

https://codereview.appspot.com/7139058/



git-svn-id: http://skia.googlecode.com/svn/trunk@7308 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/samplecode/SampleText.cpp b/samplecode/SampleText.cpp
index 20673ee..b71d844 100644
--- a/samplecode/SampleText.cpp
+++ b/samplecode/SampleText.cpp
@@ -124,6 +124,7 @@
 
     typedef SkFlattenable* (*Factory)(SkFlattenableReadBuffer&);
 
+    SK_DEVELOPER_TO_STRING()
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkPowerMode)
 
 private:
@@ -173,6 +174,13 @@
     }
 }
 
+#ifdef SK_DEVELOPER
+void SkPowerMode::toString(SkString* str) const {
+    str->append("SkPowerMode: exponent ");
+    str->appendScalar(fExp);
+}
+#endif
+
 static const struct {
     const char* fName;
     uint32_t    fFlags;