pdfviewer: fix typo

Review URL: https://codereview.chromium.org/22076007

git-svn-id: http://skia.googlecode.com/svn/trunk@10540 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/experimental/PdfViewer/chop_transparency_main.cpp b/experimental/PdfViewer/chop_transparency_main.cpp
index eab4933..c9a199c 100644
--- a/experimental/PdfViewer/chop_transparency_main.cpp
+++ b/experimental/PdfViewer/chop_transparency_main.cpp
@@ -43,7 +43,7 @@
     int width = 1;
     int height = 1;
     for (int y = 0 ; y < bm.height(); y++) {
-        for (int x = 0 ; x < bm.height(); x++) {
+        for (int x = 0 ; x < bm.width(); x++) {
             SkColor color = bm.getColor(x, y);
             if (SkColorGetA(color) != 0) {
                 height = y + 1;