fix more 64bit warnings

BUG=skia:

Review URL: https://codereview.chromium.org/147683003

git-svn-id: http://skia.googlecode.com/svn/trunk@13190 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gm/getpostextpath.cpp b/gm/getpostextpath.cpp
index 0f2eb79..68faf95 100644
--- a/gm/getpostextpath.cpp
+++ b/gm/getpostextpath.cpp
@@ -33,7 +33,7 @@
     virtual void onDraw(SkCanvas* canvas) {
         // explicitly add spaces, to test a prev. bug
         const char* text = "Ham bur ge fons";
-        size_t len = strlen(text);
+        int len = SkToInt(strlen(text));
         SkPath path;
 
         SkPaint paint;
@@ -54,7 +54,7 @@
         SkLCGRandom rand;
         SkScalar x = SkIntToScalar(20);
         SkScalar y = SkIntToScalar(100);
-        for (size_t i = 0; i < len; ++i) {
+        for (int i = 0; i < len; ++i) {
             pos[i].set(x, y + rand.nextSScalar1() * 24);
             x += widths[i];
         }