change colorfilter to return an array of frag processors

include/core/SkColorFilter.h

-
 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
-
 #ifndef SkColorFilter_DEFINED
 #define SkColorFilter_DEFINED
 
 #include "SkColor.h"
 #include "SkFlattenable.h"
+#include "SkTDArray.h"
 #include "SkXfermode.h"
 
 class SkBitmap;
 class GrProcessor;
 class GrContext;
 
 /**
  *  ColorFilters are optional objects in the drawing pipeline. When present in
  *  a paint, they are called with the "src" colors, and return new colors, which
  *  are then passed onto the next stage (either ImageFilter or Xfermode).
@@ skipping 106 matching lines @@
         are ignored.
     */
     static SkColorFilter* CreateLightingFilter(SkColor mul, SkColor add);
 
     /** Construct a colorfilter whose effect is to first apply the inner filter and then apply
      *  the outer filter to the result of the inner's.
      *  The reference counts for outer and inner are incremented.
      */
     static SkColorFilter* CreateComposeFilter(SkColorFilter* outer, SkColorFilter* inner);
 
-    /** A subclass may implement this factory function to work with the GPU backend. If the return
-        is non-NULL then the caller owns a ref on the returned object.
+    /**
+     *  A subclass may implement this factory function to work with the GPU backend.
+     *  If it returns true, then 1 or more fragment processors will have been appended to the
+     *  array, each of which has been ref'd, so that the caller is responsible for calling unref()
+     *  on them when they are finished. If more than one processor is appended, they will be
+     *  applied in FIFO order.
+     *
+     *  If the subclass returns false, then it should not modify the array at all.
      */
-    virtual GrFragmentProcessor* asFragmentProcessor(GrContext*) const;
+    virtual bool asFragmentProcessors(GrContext*, SkTDArray<GrFragmentProcessor*>*) const {

[bsalomon, 2015/03/03 17:51:01]

Does this mean we always have to malloc for the common case of 1 processor? I
wonder if we could use SkSTArray, SkAutoSTArray, or something similar.

+        return false;
+    }
 
     SK_TO_STRING_PUREVIRT()
 
     SK_DECLARE_FLATTENABLE_REGISTRAR_GROUP()
     SK_DEFINE_FLATTENABLE_TYPE(SkColorFilter)
 
 protected:
     SkColorFilter() {}
 
 private:
     typedef SkFlattenable INHERITED;
 };
 
 #endif