Add toString methods to SkImageFilter-derived classes

src/effects/SkDropShadowImageFilter.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkDropShadowImageFilter.h"
 
 #include "SkBitmap.h"
@@ skipping 118 matching lines @@
                   SkScalarCeilToInt(SkScalarMul(sigma.y(), SkIntToScalar(3))));
     if (fShadowMode == kDrawShadowAndForeground_ShadowMode) {
         bounds.join(src);
     }
     if (getInput(0) && !getInput(0)->filterBounds(bounds, ctm, &bounds)) {
         return false;
     }
     *dst = bounds;
     return true;
 }
+
+#ifndef SK_IGNORE_TO_STRING
+void SkDropShadowImageFilter::toString(SkString* str) const {
+    str->appendf("SkDropShadowImageFilter: (");
+
+    str->appendf("dX: %f ", fDx);
+    str->appendf("dY: %f ", fDy);
+    str->appendf("sigmaX: %f ", fSigmaX);
+    str->appendf("sigmaY: %f ", fSigmaY);
+
+    str->append("Color: ");
+    str->appendHex(fColor);
+
+    static const char* gModeStrings[] = {
+        "kDrawShadowAndForeground", "kDrawShadowOnly"
+    };
+
+    SK_COMPILE_ASSERT(kShadowModeCount == SK_ARRAY_COUNT(gModeStrings), enum_mismatch);
+
+    str->appendf(" mode: %s", gModeStrings[fShadowMode]);
+
+    str->append(")");
+}
+#endif