Fix matrix3d transform under page zoom

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

Index: third_party/WebKit/Source/platform/transforms/TransformationMatrix.cpp
diff --git a/third_party/WebKit/Source/platform/transforms/TransformationMatrix.cpp b/third_party/WebKit/Source/platform/transforms/TransformationMatrix.cpp
index f0cb81c6acf0e700198ea9a2705f3f1dab08d365..6b7411b86608e5764f5b816337ce6dce6bfc4aa7 100644
--- a/third_party/WebKit/Source/platform/transforms/TransformationMatrix.cpp
+++ b/third_party/WebKit/Source/platform/transforms/TransformationMatrix.cpp
@@ -1266,6 +1266,16 @@ TransformationMatrix& TransformationMatrix::applyTransformOrigin(double x,
   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