Fix precision error in https://codereview.chromium.org/1188433011/

src/core/SkMatrix.cpp

 /*
  * Copyright 2006 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 "SkMatrix.h"
 #include "SkFloatBits.h"
 #include "SkString.h"
@@ skipping 768 matching lines @@
         affine[kAScaleX] = this->fMat[kMScaleX];
         affine[kASkewY] = this->fMat[kMSkewY];
         affine[kASkewX] = this->fMat[kMSkewX];
         affine[kAScaleY] = this->fMat[kMScaleY];
         affine[kATransX] = this->fMat[kMTransX];
         affine[kATransY] = this->fMat[kMTransY];
     }
     return true;
 }
 
-void SkMatrix::ComputeInv(SkScalar dst[9], const SkScalar src[9], SkScalar invDet, bool isPersp) {
+void SkMatrix::ComputeInv(SkScalar dst[9], const SkScalar src[9], double invDet, bool isPersp) {
     SkASSERT(src != dst);
     SkASSERT(src && dst);
 
     if (isPersp) {
         dst[kMScaleX] = scross_dscale(src[kMScaleY], src[kMPersp2], src[kMTransY], src[kMPersp1], invDet);
         dst[kMSkewX]  = scross_dscale(src[kMTransX], src[kMPersp1], src[kMSkewX],  src[kMPersp2], invDet);
         dst[kMTransX] = scross_dscale(src[kMSkewX],  src[kMTransY], src[kMTransX], src[kMScaleY], invDet);
 
         dst[kMSkewY]  = scross_dscale(src[kMTransY], src[kMPersp0], src[kMSkewY],  src[kMPersp2], invDet);
         dst[kMScaleY] = scross_dscale(src[kMScaleX], src[kMPersp2], src[kMTransX], src[kMPersp0], invDet);
@@ skipping 1016 matching lines @@
         rotation1->fX = cos1;
         rotation1->fY = sin1;
     }
     if (rotation2) {
         rotation2->fX = cos2;
         rotation2->fY = sin2;
     }
 
     return true;
 }