fix utf32 text in subpixel mode

BUG=skia:2568
R=scroggo@google.com, anders@kilohearts.com

Author: reed@google.com

Review URL: https://codereview.chromium.org/290893003

git-svn-id: http://skia.googlecode.com/svn/trunk@14789 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/core/SkPaint.cpp b/src/core/SkPaint.cpp
index 88e5b43..7ac2f07 100644
--- a/src/core/SkPaint.cpp
+++ b/src/core/SkPaint.cpp
@@ -924,7 +924,7 @@
     SkASSERT(text != NULL);
 
     const int32_t* ptr = *(const int32_t**)text;
-    SkUnichar uni = *--ptr;
+    SkUnichar uni = *ptr++;
     *text = (const char*)ptr;
     return cache->getUnicharMetrics(uni, x, y);
 }