Magnifier gpu path fix

The y axis was inverted for the offset, which should have been computed on the other side of the magnifying rectangle.

BUG=
R=bsalomon@google.com, senorblanco@google.com, senorblanco@chromium.org

Author: sugoi@chromium.org

Review URL: https://codereview.chromium.org/28273005

git-svn-id: http://skia.googlecode.com/svn/trunk@11883 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gm/imagemagnifier.cpp b/gm/imagemagnifier.cpp
index f073e33..ae639d3 100644
--- a/gm/imagemagnifier.cpp
+++ b/gm/imagemagnifier.cpp
@@ -38,7 +38,7 @@
         SkPaint paint;
         paint.setImageFilter(
             new SkMagnifierImageFilter(
-                SkRect::MakeXYWH(SkIntToScalar(125), SkIntToScalar(125),
+                SkRect::MakeXYWH(SkIntToScalar(100), SkIntToScalar(100),
                                  SkIntToScalar(WIDTH / 2),
                                  SkIntToScalar(HEIGHT / 2)),
                 100))->unref();