GLProgramsTest can now randomly create a tree of GrFragmentProcessors instead of a linear pipeline

src/gpu/effects/GrXfermodeFragmentProcessor.cpp

Index: src/gpu/effects/GrXfermodeFragmentProcessor.cpp
diff --git a/src/gpu/effects/GrXfermodeFragmentProcessor.cpp b/src/gpu/effects/GrXfermodeFragmentProcessor.cpp
index aa47541cd0309e4a8c9f6f52d3670dcfa5926297..3cb56d07f7ea2ce74d3a5d08f0118781293a3958 100644
--- a/src/gpu/effects/GrXfermodeFragmentProcessor.cpp
+++ b/src/gpu/effects/GrXfermodeFragmentProcessor.cpp
@@ -147,19 +147,13 @@ const GrFragmentProcessor* GrXfermodeFragmentProcessor::CreateFromTwoProcessors(
     }
     switch (mode) {
         case SkXfermode::kClear_Mode:
-            SkDebugf("CreateFromTwoProcessors() should not be used with kClear_Mode. "
-                     "Use GrConstColorProcessor.\n");
             return GrConstColorProcessor::Create(GrColor_TRANS_BLACK,
                                                  GrConstColorProcessor::kIgnore_InputMode);
             break;
         case SkXfermode::kSrc_Mode:
-            SkDebugf("CreateFromTwoProcessors() should not be used with kSrc_Mode. "
-                     "Use the src processor directly.\n");
             return SkRef(src);
             break;
         case SkXfermode::kDst_Mode:
-            SkDebugf("CreateFromTwoProcessors() should not be used with kDst_Mode. "
-                     "Use the dst processor directly.\n");
             return SkRef(dst);
             break;
         default: