[PDF] Refactor SkPDFFont to enable font/cmap subsetting.

Patch from Arthur Hsu, original CL: http://codereview.appspot.com/4633050/

Committed: http://code.google.com/p/skia/source/detail?r=1943
Reverted: http://code.google.com/p/skia/source/detail?r=1944

Review URL: http://codereview.appspot.com/4811049

git-svn-id: http://skia.googlecode.com/svn/trunk@1956 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/include/pdf/SkBitSet.h b/include/pdf/SkBitSet.h
index 84d52e5..01d9c6c 100755
--- a/include/pdf/SkBitSet.h
+++ b/include/pdf/SkBitSet.h
@@ -40,12 +40,12 @@
 
     /** Test if bit index is set.
      */
-    bool isBitSet(int index);
+    bool isBitSet(int index) const;
 
     /** Or bits from source.  false is returned if this doesn't have the same
      *  bit count as source.
      */
-    bool orBits(SkBitSet& source);
+    bool orBits(const SkBitSet& source);
 
 private:
     SkAutoFree fBitData;
@@ -53,7 +53,7 @@
     size_t fDwordCount;
     size_t fBitCount;
 
-    uint32_t* internalGet(int index) {
+    uint32_t* internalGet(int index) const {
         SkASSERT((size_t)index < fBitCount);
         size_t internalIndex = index / 32;
         SkASSERT(internalIndex < fDwordCount);