don't normalize after perspective concat

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 551 matching lines @@
 
 static inline float muladdmul(float a, float b, float c, float d) {
     return SkDoubleToFloat((double)a * b + (double)c * d);
 }
 
 static inline float rowcol3(const float row[], const float col[]) {
     return row[0] * col[0] + row[1] * col[3] + row[2] * col[6];
 }
 
 static void normalize_perspective(SkScalar mat[9]) {
-    if (SkScalarAbs(mat[SkMatrix::kMPersp2]) > 1) {
-        for (int i = 0; i < 9; i++)
-            mat[i] = SkScalarHalf(mat[i]);
-    }
+    // If it was interesting to never store the last element, we could divide all 8 other
+    // elements here by the 9th, making it 1.0...
+    //
+    // When SkScalar was SkFixed, we would sometimes rescale the entire matrix to keep its
+    // component values from getting too large. This is not a concern when using floats/doubles,
+    // so we do nothing now.
 }
 
 static bool only_scale_and_translate(unsigned mask) {
     return 0 == (mask & (SkMatrix::kAffine_Mask | SkMatrix::kPerspective_Mask));
 }
 
 void SkMatrix::setConcat(const SkMatrix& a, const SkMatrix& b) {
     TypeMask aType = a.getType();
     TypeMask bType = b.getType();
 
@@ skipping 1164 matching lines @@
         rotation1->fX = cos1;
         rotation1->fY = sin1;
     }
     if (rotation2) {
         rotation2->fX = cos2;
         rotation2->fY = sin2;
     }
 
     return true;
 }