DM warning-free on win64

Review URL: https://codereview.chromium.org/805543002
diff --git a/tests/PaintTest.cpp b/tests/PaintTest.cpp
index c307aa9..bf22de1 100644
--- a/tests/PaintTest.cpp
+++ b/tests/PaintTest.cpp
@@ -21,7 +21,7 @@
 static size_t uni_to_utf8(const SkUnichar src[], void* dst, int count) {
     char* u8 = (char*)dst;
     for (int i = 0; i < count; ++i) {
-        int n = SkUTF8_FromUnichar(src[i], u8);
+        int n = SkToInt(SkUTF8_FromUnichar(src[i], u8));
         u8 += n;
     }
     return u8 - (char*)dst;
@@ -30,7 +30,7 @@
 static size_t uni_to_utf16(const SkUnichar src[], void* dst, int count) {
     uint16_t* u16 = (uint16_t*)dst;
     for (int i = 0; i < count; ++i) {
-        int n = SkUTF16_FromUnichar(src[i], u16);
+        int n = SkToInt(SkUTF16_FromUnichar(src[i], u16));
         u16 += n;
     }
     return (char*)u16 - (char*)dst;