Fix matrix3d transform under page zoom

third_party/WebKit/Source/platform/transforms/TransformationMatrix.cpp

 /*
  * Copyright (C) 2005, 2006 Apple Computer, Inc.  All rights reserved.
  * Copyright (C) 2009 Torch Mobile, Inc.
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 1248 matching lines @@
 }
 
 TransformationMatrix& TransformationMatrix::applyTransformOrigin(double x,
                                                                  double y,
                                                                  double z) {
   translateRight3d(x, y, z);
   translate3d(-x, -y, -z);
   return *this;
 }
 
+TransformationMatrix& TransformationMatrix::zoom(double zoomFactor) {
+  m_matrix[0][3] /= zoomFactor;
+  m_matrix[1][3] /= zoomFactor;
+  m_matrix[2][3] /= zoomFactor;
+  m_matrix[3][0] *= zoomFactor;
+  m_matrix[3][1] *= zoomFactor;
+  m_matrix[3][2] *= zoomFactor;
+  return *this;
+}
+
 // Calculates *this = *this * mat.
 // Note: A * B means that the transforms represented by A happen first, and
 // then the transforms represented by B. That is, the matrix A * B corresponds
 // to a CSS transform list <transform-function-A> <transform-function-B>.
 // Some branches of this function may make use of the fact that
 // transpose(A * B) == transpose(B) * transpose(A); remember that
 // m_matrix[a][b] is matrix element row b, col a.
 // FIXME: As of 2016-05-04, the ARM64 branch is NOT triggered by tests on the CQ
 // bots, see crbug.com/477892 and crbug.com/584508.
 TransformationMatrix& TransformationMatrix::multiply(
@@ skipping 642 matching lines @@
       decomposition.translateZ, decomposition.scaleX, decomposition.scaleY,
       decomposition.scaleZ, decomposition.skewXY, decomposition.skewXZ,
       decomposition.skewYZ, decomposition.quaternionX,
       decomposition.quaternionY, decomposition.quaternionZ,
       decomposition.quaternionW, decomposition.perspectiveX,
       decomposition.perspectiveY, decomposition.perspectiveZ,
       decomposition.perspectiveW);
 }
 
 }  // namespace blink