Distance field fixes for Android

src/core/SkDistanceFieldGen.cpp

Index: src/core/SkDistanceFieldGen.cpp
diff --git a/src/core/SkDistanceFieldGen.cpp b/src/core/SkDistanceFieldGen.cpp
index 43e92ba8fa10a6bebf31231f760d03471e7c3243..a829fd47410fa93381f8f02c92183a7a46df9f90 100755
--- a/src/core/SkDistanceFieldGen.cpp
+++ b/src/core/SkDistanceFieldGen.cpp
@@ -336,10 +336,10 @@ bool SkGenerateDistanceFieldFromImage(unsigned char* distanceField,
     SkASSERT(NULL != image);
 
     // the final distance field will have additional texels on each side to handle
-    // the maximum distance
+    // the maximum distance + 1 for bilerp
     // we expand our temp data by one more on each side to simplify
     // the scanning code -- will always be treated as infinitely far away
-    int pad = distanceMagnitude+1;
+    int pad = distanceMagnitude+2;
 
     // set params for distance field data
     int dataWidth = width + 2*pad;