Add toString methods to SkImageFilter-derived classes

src/effects/SkTableColorFilter.cpp

Index: src/effects/SkTableColorFilter.cpp
diff --git a/src/effects/SkTableColorFilter.cpp b/src/effects/SkTableColorFilter.cpp
index 942bae7d06361d2b136cda1bcff482eab71dcc22..e12b3d78ec2d0ed0e2f6d0ea90da9ebd322a78bc 100644
--- a/src/effects/SkTableColorFilter.cpp
+++ b/src/effects/SkTableColorFilter.cpp
@@ -155,7 +155,32 @@ void SkTable_ColorFilter::filterSpan(const SkPMColor src[], int count,
 
 #ifndef SK_IGNORE_TO_STRING
 void SkTable_ColorFilter::toString(SkString* str) const {
-    str->append("SkTable_ColorFilter");
+    const uint8_t* table = fStorage;
+    const uint8_t* tableA = gIdentityTable;
+    const uint8_t* tableR = gIdentityTable;
+    const uint8_t* tableG = gIdentityTable;
+    const uint8_t* tableB = gIdentityTable;
+    if (fFlags & kA_Flag) {
+        tableA = table; table += 256;
+    }
+    if (fFlags & kR_Flag) {
+        tableR = table; table += 256;
+    }
+    if (fFlags & kG_Flag) {
+        tableG = table; table += 256;
+    }
+    if (fFlags & kB_Flag) {
+        tableB = table;
+    }
+
+    str->append("SkTable_ColorFilter (");
+
+    for (int i = 0; i < 256; ++i) {
+        str->appendf("%d: %d,%d,%d,%d\n",
+                     i, tableR[i], tableG[i], tableB[i], tableA[i]);
+    }
+
+    str->append(")");
 }
 #endif