Fix a few clang errors while trying to build tools target.

src/gpu/gl/GrGLEffectMatrix.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrGLEffectMatrix.h"
 #include "GrDrawEffect.h"
 #include "GrTexture.h"
@@ skipping 30 matching lines @@
         key |= kIdentity_MatrixType;
     }
     return key;
 }
 
 GrSLType GrGLEffectMatrix::emitCode(GrGLShaderBuilder* builder,
                                     EffectKey key,
                                     const char** fsCoordName,
                                     const char** vsCoordName,
                                     const char* suffix) {
-    GrSLType varyingType;
+    GrSLType varyingType = kVoid_GrSLType;
     const char* uniName;
     key &= kKeyMask;
     switch (key & kMatrixTypeKeyMask) {
         case kIdentity_MatrixType:
             fUniType = kVoid_GrSLType;
             varyingType = kVec2f_GrSLType;
             break;
         case kTrans_MatrixType:
             fUniType = kVec2f_GrSLType;
             uniName = "StageTranslate";
@@ skipping 167 matching lines @@
             if (!fPrevMatrix.cheapEqualTo(combined)) {
                 uniformManager.setSkMatrix(fUni, combined);
                 fPrevMatrix = combined;
             }
             break;
         }
         default:
             GrCrash("Unexpected uniform type.");
     }
 }