fix warnings

git-svn-id: http://skia.googlecode.com/svn/trunk@1129 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/samplecode/SampleStrokeText.cpp b/samplecode/SampleStrokeText.cpp
index a527bd2..e75bb54 100644
--- a/samplecode/SampleStrokeText.cpp
+++ b/samplecode/SampleStrokeText.cpp
@@ -23,7 +23,7 @@
     SkScalar x = 0;
     SkScalar width;
     SkPath p;
-    for (int i = 0; i < strlen(chars); i++) {
+    for (size_t i = 0; i < strlen(chars); i++) {
         original.getTextPath(&chars[i], 1, x, 0, &p);
         path.addPath(p);
         original.getTextWidths(&chars[i], 1, &width);
@@ -69,7 +69,7 @@
     SkScalar x = 0;
     SkScalar width;
     SkPath p;
-    for (int i = 0; i < strlen(chars); i++) {
+    for (size_t i = 0; i < strlen(chars); i++) {
         original.getTextPath(&chars[i], 1, x, 0, &p);
         path.addPath(p);
         original.getTextWidths(&chars[i], 1, &width);