Add default ctor to SkMask

bench/BlurRectBench.cpp

Index: bench/BlurRectBench.cpp
diff --git a/bench/BlurRectBench.cpp b/bench/BlurRectBench.cpp
index b8a72118153e33cb70a45fc111a5fce7bccceb2d..237ed530e3c7dc9e2cffa32ed6499b8d79584757 100644
--- a/bench/BlurRectBench.cpp
+++ b/bench/BlurRectBench.cpp
@@ -63,7 +63,7 @@ protected:
         preBenchSetup(r);
 
         for (int i = 0; i < loops; i++) {
-            makeBlurryRect(r);
+            this->makeBlurryRect(r);
         }
     }
 
@@ -101,9 +101,7 @@ private:
 class BlurRectSeparableBench: public BlurRectBench {
 
 public:
-    BlurRectSeparableBench(SkScalar rad) : INHERITED(rad) {
-        fSrcMask.fImage = nullptr;
-    }
+    BlurRectSeparableBench(SkScalar rad) : INHERITED(rad) { }
 
     ~BlurRectSeparableBench() {
         SkMask::FreeImage(fSrcMask.fImage);
@@ -144,7 +142,6 @@ protected:
 
     void makeBlurryRect(const SkRect&) override {
         SkMask mask;
-        mask.fImage = nullptr;
         SkBlurMask::BoxBlur(&mask, fSrcMask, SkBlurMask::ConvertRadiusToSigma(this->radius()),
                             kNormal_SkBlurStyle, kHigh_SkBlurQuality);
         SkMask::FreeImage(mask.fImage);
@@ -171,7 +168,6 @@ protected:
 
     void makeBlurryRect(const SkRect&) override {
         SkMask mask;
-        mask.fImage = nullptr;
         SkBlurMask::BlurGroundTruth(SkBlurMask::ConvertRadiusToSigma(this->radius()),
                                     &mask, fSrcMask, kNormal_SkBlurStyle);
         SkMask::FreeImage(mask.fImage);