Avoid copies in SkMasks constructor

src/codec/SkMasks.h

Index: src/codec/SkMasks.h
diff --git a/src/codec/SkMasks.h b/src/codec/SkMasks.h
index 082370466828009f781f6cbdb20d07d7379b6504..9606cbfbeb9760a64ad33e7656f50ea59fe20a15 100644
--- a/src/codec/SkMasks.h
+++ b/src/codec/SkMasks.h
@@ -52,10 +52,10 @@ public:
      * Get a color component
      *
      */
-    uint8_t getRed(uint32_t pixel);
-    uint8_t getGreen(uint32_t pixel);
-    uint8_t getBlue(uint32_t pixel);
-    uint8_t getAlpha(uint32_t pixel);
+    uint8_t getRed(uint32_t pixel) const;
+    uint8_t getGreen(uint32_t pixel) const;
+    uint8_t getBlue(uint32_t pixel) const;
+    uint8_t getAlpha(uint32_t pixel) const;
 
     /*
      *
@@ -63,7 +63,7 @@ public:
      * The alpha mask may be used in other decoding modes
      *
      */
-     uint32_t getAlphaMask() {
+     uint32_t getAlphaMask() const {
         return fAlpha.mask;
      }
 
@@ -71,11 +71,11 @@ private:
 
     /*
      *
-     * Constrcutor
+     * Constructor
      *
      */
-    SkMasks(const MaskInfo red, const MaskInfo green, const MaskInfo blue,
-            const MaskInfo alpha);
+    SkMasks(const MaskInfo& red, const MaskInfo& green, const MaskInfo& blue,
+            const MaskInfo& alpha);
 
     const MaskInfo fRed;
     const MaskInfo fGreen;