Fix for MSAN unintialized value

src/gpu/effects/GrTextureDomain.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrTextureDomainEffect_DEFINED
 #define GrTextureDomainEffect_DEFINED
 
@@ skipping 77 matching lines @@
 
     /**
      * A GrGLProcessor subclass that corresponds to a GrProcessor subclass that uses GrTextureDomain
      * should include this helper. It generates the texture domain GLSL, produces the part of the
      * effect key that reflects the texture domain code, and performs the uniform uploads necessary
      * for texture domains.
      */
     class GLDomain {
     public:
         GLDomain() {
-            fPrevDomain[0] = SK_FloatNaN;
+            for (int i = 0; i < kPrevDomainCount; i++) {
+                fPrevDomain[i] = SK_FloatNaN;
+            }
             SkDEBUGCODE(fMode = (Mode) -1;)
         }
 
         /**
          * Call this from GrGLProcessor::emitCode() to sample the texture W.R.T. the domain and
          * mode.
          *
          * @param outcolor  name of vec4 variable to hold the sampled color.
          * @param inCoords  name of vec2 variable containing the coords to be used with the domain.
          *                  It is assumed that this is a variable and not an expression.
@@ skipping 21 matching lines @@
         /**
          * GrGLProcessor::GenKey() must call this and include the returned value in it's computed
          * key. The returned will be limited to the lower kDomainKeyBits bits.
          */
         static uint32_t DomainKey(const GrTextureDomain& domain) {
             GR_STATIC_ASSERT(kModeCount <= 4);
             return domain.mode();
         }
 
     private:
+        static const int kPrevDomainCount = 4;
         SkDEBUGCODE(Mode                      fMode;)
         GrGLProgramDataManager::UniformHandle fDomainUni;
         SkString                              fDomainName;
-        GrGLfloat                             fPrevDomain[4];
+        GrGLfloat                             fPrevDomain[kPrevDomainCount];
     };
 
 protected:
     Mode    fMode;
     SkRect  fDomain;
     int     fIndex;
 
     typedef GrSingleTextureEffect INHERITED;
 };
 
@@ skipping 36 matching lines @@
     bool onIsEqual(const GrFragmentProcessor&) const override;
 
     void onComputeInvariantOutput(GrInvariantOutput* inout) const override;
 
     GR_DECLARE_FRAGMENT_PROCESSOR_TEST;
 
     typedef GrSingleTextureEffect INHERITED;
 };
 
 #endif