Third wave of Win64 warning cleanup

https://codereview.chromium.org/27487003/



git-svn-id: http://skia.googlecode.com/svn/trunk@11817 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gm/shadertext.cpp b/gm/shadertext.cpp
index adcb25e..412516b 100644
--- a/gm/shadertext.cpp
+++ b/gm/shadertext.cpp
@@ -183,7 +183,7 @@
         static const int rowHeight = 60;
         static const int colWidth = 300;
         canvas->save();
-        for (size_t s = 0; s < SK_ARRAY_COUNT(shaders); s++) {
+        for (int s = 0; s < static_cast<int>(SK_ARRAY_COUNT(shaders)); s++) {
             canvas->save();
             int i = 2*s;
             canvas->translate(SkIntToScalar((i / testsPerCol) * colWidth),