Add printing of SkColorFilter-derived classes to debugger

src/effects/SkTableColorFilter.cpp

Index: src/effects/SkTableColorFilter.cpp
===================================================================
--- src/effects/SkTableColorFilter.cpp	(revision 9237)
+++ src/effects/SkTableColorFilter.cpp	(working copy)
@@ -4,6 +4,7 @@
 #include "SkColorPriv.h"
 #include "SkFlattenableBuffers.h"
 #include "SkUnPreMultiply.h"
+#include "SkString.h"
 
 class SkTable_ColorFilter : public SkColorFilter {
 public:
@@ -47,6 +48,8 @@
     virtual void filterSpan(const SkPMColor src[], int count,
                             SkPMColor dst[]) const SK_OVERRIDE;
 
+    SkDEVCODE(virtual void toString(SkString* str) const SK_OVERRIDE;)
+
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkTable_ColorFilter)
 
     enum {
@@ -148,6 +151,12 @@
     }
 }
 
+#ifdef SK_DEVELOPER
+void SkTable_ColorFilter::toString(SkString* str) const {
+    str->append("SkTable_ColorFilter");
+}
+#endif
+
 static const uint8_t gCountNibBits[] = {
     0, 1, 1, 2,
     1, 2, 2, 3,