fix text rotation for skia

My initial guess for text rotation worked for scaled
but not skewed or rotated.

R=dsinclair@chromium.org,reed@google.com

Review-Url: https://codereview.chromium.org/2178623002
diff --git a/core/fxge/skia/fx_skia_device.cpp b/core/fxge/skia/fx_skia_device.cpp
index 3c7ce7e..a5c509e 100644
--- a/core/fxge/skia/fx_skia_device.cpp
+++ b/core/fxge/skia/fx_skia_device.cpp
@@ -137,7 +137,7 @@
 // use when pdf's y-axis points up insead of down
 SkMatrix ToFlippedSkMatrix(const CFX_Matrix& m) {
   SkMatrix skMatrix;
-  skMatrix.setAll(m.a, m.b, m.e, -m.c, -m.d, m.f, 0, 0, 1);
+  skMatrix.setAll(m.a, -m.b, m.e, m.c, -m.d, m.f, 0, 0, 1);
   return skMatrix;
 }