change back to method for localmatrix imagefilter

This method is different from MatrixFilter, in that MatrixFilter does not require a pre-existing
filter, but LocalM does. Also change the comment to be more general, as there is no promise that
we return a different subclass, and certainly not a specific subclass.

This pattern of obj->newWithModifiers() also more closely matches the pattern in SkImage (newSubset).

BUG=skia:

Review URL: https://codereview.chromium.org/1402133002

1 files changed, 6 insertions, 7 deletions

diff --git a/include/core/SkImageFilter.h b/include/core/SkImageFilter.h
index 0a3f7b8492..3a7cb23d5e 100644
--- a/include/core/SkImageFilter.h
+++ b/include/core/SkImageFilter.h
@@ -230,19 +230,18 @@ public:
     bool canComputeFastBounds() const;
 
     /**
+     *  If this filter can be represented by another filter + a localMatrix, return that filter,
+     *  else return null.
+     */
+    SkImageFilter* newWithLocalMatrix(const SkMatrix& matrix) const;
+
+    /**
      * Create an SkMatrixImageFilter, which transforms its input by the given matrix.
      */
     static SkImageFilter* CreateMatrixFilter(const SkMatrix& matrix,
                                              SkFilterQuality,
                                              SkImageFilter* input = NULL);
 
-    /**
-     * Create an SkLocalMatrixImageFilter, which transform the filter parameters
-     * of its inputs by the given matrix.
-     */
-    static SkImageFilter* CreateLocalMatrixFilter(const SkMatrix& matrix,
-                                                  SkImageFilter* input);
-
 #if SK_SUPPORT_GPU
     /**
      * Wrap the given texture in a texture-backed SkBitmap.