[PDF] Improve efficiency of glyph id collection during font subsetting.

Patch from Arthur Hsu, original CL: http://codereview.appspot.com/4828044/

Review URL: http://codereview.appspot.com/4798057

git-svn-id: http://skia.googlecode.com/svn/trunk@1978 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/include/pdf/SkBitSet.h b/include/pdf/SkBitSet.h
index 01d9c6c..b72a895 100755
--- a/include/pdf/SkBitSet.h
+++ b/include/pdf/SkBitSet.h
@@ -18,6 +18,7 @@
 #define SkBitSet_DEFINED
 
 #include "SkTypes.h"
+#include "SkTDArray.h"
 
 class SkBitSet {
 public:
@@ -47,6 +48,10 @@
      */
     bool orBits(const SkBitSet& source);
 
+    /** Export set bits to unsigned int array. (used in font subsetting)
+     */
+    void exportTo(SkTDArray<uint32_t>* array) const;
+
 private:
     SkAutoFree fBitData;
     // Dword (32-bit) count of the bitset.