Add bigtileimagefilter GM & improvements to toString

src/effects/SkXfermodeImageFilter.cpp

 /*
  * Copyright 2013 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkXfermodeImageFilter.h"
 #include "SkCanvas.h"
 #include "SkDevice.h"
@@ skipping 87 matching lines @@
     return true;
 }
 
 #ifndef SK_IGNORE_TO_STRING
 void SkXfermodeImageFilter::toString(SkString* str) const {
     str->appendf("SkXfermodeImageFilter: (");
     str->appendf("xfermode: (");
     if (fMode) {
         fMode->toString(str);
     }
-    str->append("))");
+    str->append(")");
+    if (this->getInput(0)) {
+        str->appendf("foreground: (");
+        this->getInput(0)->toString(str);
+        str->appendf(")");
+    }
+    if (this->getInput(1)) {
+        str->appendf("background: (");
+        this->getInput(1)->toString(str);
+        str->appendf(")");
+    }
+    str->append(")");
 }
 #endif
 
 #if SK_SUPPORT_GPU
 
 bool SkXfermodeImageFilter::canFilterImageGPU() const {
     return fMode && fMode->asFragmentProcessor(NULL, NULL) && !cropRectIsSet();
 }
 
 bool SkXfermodeImageFilter::filterImageGPU(Proxy* proxy,
@@ skipping 70 matching lines @@
                           SkMatrix::I(), srcRect);
 
     offset->fX = backgroundOffset.fX;
     offset->fY = backgroundOffset.fY;
     WrapTexture(dst, src.width(), src.height(), result);
     return true;
 }
 
 #endif