add compose-colorfilter

include/effects/SkModeColorFilter.h

Index: include/effects/SkModeColorFilter.h
diff --git a/include/effects/SkModeColorFilter.h b/include/effects/SkModeColorFilter.h
new file mode 100644
index 0000000000000000000000000000000000000000..16c6e13359545af766839c4af90ae00a891d0fbc
--- /dev/null
+++ b/include/effects/SkModeColorFilter.h
@@ -0,0 +1,63 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkModeColorFilter_DEFINED
+#define SkModeColorFilter_DEFINED
+
+#include "SkColorFilter.h"
+#include "SkColorPriv.h"
+#include "SkString.h"
+#include "SkXfermode.h"
+
+class SkModeColorFilter : public SkColorFilter {
+public:
+    SkModeColorFilter(SkColor color, SkXfermode::Mode mode) {
+        fColor = color;
+        fMode = mode;
+        this->updateCache();
+    };
+
+    SkColor getColor() const { return fColor; }
+    SkXfermode::Mode getMode() const { return fMode; }
+    SkPMColor getPMColor() const { return fPMColor; }
+
+    bool asColorMode(SkColor*, SkXfermode::Mode*) const SK_OVERRIDE;
+    uint32_t getFlags() const SK_OVERRIDE;
+    void filterSpan(const SkPMColor shader[], int count, SkPMColor result[]) const SK_OVERRIDE;
+    void filterSpan16(const uint16_t shader[], int count, uint16_t result[]) const SK_OVERRIDE;
+
+#ifndef SK_IGNORE_TO_STRING
+    void toString(SkString* str) const SK_OVERRIDE {
+        str->append("SkModeColorFilter: color: 0x");
+        str->appendHex(fColor);
+        str->append(" mode: ");
+        str->append(SkXfermode::ModeName(fMode));
+    }
+#endif
+
+#if SK_SUPPORT_GPU
+    GrFragmentProcessor* asFragmentProcessor(GrContext*) const SK_OVERRIDE;
+#endif
+    SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkModeColorFilter)
+
+protected:
+    void flatten(SkWriteBuffer&) const SK_OVERRIDE;
+
+private:
+    SkColor             fColor;
+    SkXfermode::Mode    fMode;
+    // cache
+    SkPMColor           fPMColor;
+    SkXfermodeProc      fProc;
+    SkXfermodeProc16    fProc16;
+
+    void updateCache();
+
+    typedef SkColorFilter INHERITED;
+};
+
+#endif