Move SkComposeImageFilter into its own {.h, .cpp} files

include/effects/SkTestImageFilters.h

Index: include/effects/SkTestImageFilters.h
diff --git a/include/effects/SkTestImageFilters.h b/include/effects/SkTestImageFilters.h
index c38c03793b39ea13d8a92ba382684996021baeb6..e848ff106899c3af076229af76340447ea500ff3 100755
--- a/include/effects/SkTestImageFilters.h
+++ b/include/effects/SkTestImageFilters.h
@@ -4,26 +4,6 @@
 #include "SkImageFilter.h"
 #include "SkPoint.h"
 
-class SK_API SkComposeImageFilter : public SkImageFilter {
-public:
-    SkComposeImageFilter(SkImageFilter* outer, SkImageFilter* inner) : INHERITED(outer, inner) {}
-    virtual ~SkComposeImageFilter();
-
-    SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkComposeImageFilter)
-
-protected:
-    SkComposeImageFilter(SkFlattenableReadBuffer& buffer);
-
-    virtual bool onFilterImage(Proxy*, const SkBitmap& src, const SkMatrix&,
-                               SkBitmap* result, SkIPoint* loc) SK_OVERRIDE;
-    virtual bool onFilterBounds(const SkIRect&, const SkMatrix&, SkIRect*) SK_OVERRIDE;
-
-private:
-    typedef SkImageFilter INHERITED;
-};
-
-///////////////////////////////////////////////////////////////////////////////
-
 // Fun mode that scales down (only) and then scales back up to look pixelated
 class SK_API SkDownSampleImageFilter : public SkImageFilter {
 public: