Begin making SkPerlinNoiseShader const.

include/effects/SkPerlinNoiseShader.h

Index: include/effects/SkPerlinNoiseShader.h
diff --git a/include/effects/SkPerlinNoiseShader.h b/include/effects/SkPerlinNoiseShader.h
index dd89c70925954deefd9fa6d7f05e4335454f9465..a7b4d49f56de2fe038fa86f2d57d441ee47399fe 100644
--- a/include/effects/SkPerlinNoiseShader.h
+++ b/include/effects/SkPerlinNoiseShader.h
@@ -82,10 +82,6 @@ private:
                         const SkISize* tileSize = NULL);
     virtual ~SkPerlinNoiseShader();
 
-    void setTileSize(const SkISize&);
-
-    void initPaint(PaintingData& paintingData);
-
     SkScalar noise2D(int channel, const PaintingData& paintingData,
                      const StitchData& stitchData, const SkPoint& noiseVector);
 
@@ -94,13 +90,17 @@ private:
 
     SkPMColor shade(const SkPoint& point, StitchData& stitchData);
 
-    SkPerlinNoiseShader::Type fType;
-    SkScalar fBaseFrequencyX;
-    SkScalar fBaseFrequencyY;
-    int fNumOctaves;
-    SkScalar fSeed;
-    SkISize fTileSize;
-    bool fStitchTiles;
+    // TODO (scroggo): Once all SkShaders are created from a factory, and we have removed the
+    // constructor that creates SkPerlinNoiseShader from an SkReadBuffer, several fields can
+    // be made constant.

[Dominik Grewe, 2014/02/18 15:00:33]

Is it always feasible to make all fields const? If so, that would be great. I
haven't really thought about that yet, but it feels like the right thing to do
when making effects immutable.
I'm just worried that there might be some initialization code in a constructor
that you can't easily place into an initializer list. But maybe there isn't.

All effects currently have constructors that take an SkReadBuffer as parameter.
If we wanted to get rid of them (which we'd have to as you said above), maybe we
can introduce a macro similar to
SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS but using the factory
methods instead. Would be a separate patch I suppose :)

[scroggo, 2014/02/18 16:42:57]

I don't know of any other way to make them immutable.
That may be so. I tend to think that's a bridge we can cross when we get there.

+    /*const*/ SkPerlinNoiseShader::Type fType;
+    /*const*/ SkScalar                  fBaseFrequencyX;
+    /*const*/ SkScalar                  fBaseFrequencyY;
+    /*const*/ int                       fNumOctaves;
+    /*const*/ SkScalar                  fSeed;
+    /*const*/ SkISize                   fTileSize;
+    /*const*/ bool                      fStitchTiles;
+    // TODO (scroggo): Once setContext creates a new object, place this on that object.
     SkMatrix fMatrix;
 
     PaintingData* fPaintingData;