Revert of remove colorfilter native-565 support. complicating w/ no real value.

src/effects/SkColorMatrixFilter.cpp

Index: src/effects/SkColorMatrixFilter.cpp
diff --git a/src/effects/SkColorMatrixFilter.cpp b/src/effects/SkColorMatrixFilter.cpp
index 319617016c20dec09b32edd773d75747d435458a..a63666e4c0dd4d114a06510da13d2dcb01d87731 100644
--- a/src/effects/SkColorMatrixFilter.cpp
+++ b/src/effects/SkColorMatrixFilter.cpp
@@ -137,6 +137,9 @@
     result[3] = a;
 }
 
+#define kNO_ALPHA_FLAGS (SkColorFilter::kAlphaUnchanged_Flag |  \
+                         SkColorFilter::kHasFilter16_Flag)
+
 // src is [20] but some compilers won't accept __restrict__ on anything
 // but an raw pointer or reference
 void SkColorMatrixFilter::initState(const SkScalar* SK_RESTRICT src) {
@@ -178,7 +181,7 @@
         fProc = shiftIs16 ? General16 : General;
         fFlags = changesAlpha ? 0 : SkColorFilter::kAlphaUnchanged_Flag;
     } else {
-        fFlags = SkColorFilter::kAlphaUnchanged_Flag;
+        fFlags = kNO_ALPHA_FLAGS;
 
         int32_t needsScale = (array[SkColorMatrix::kR_Scale] - one) |
                              (array[SkColorMatrix::kG_Scale] - one) |
@@ -357,6 +360,40 @@
             // re-prepremultiply if needed
             dst[i] = SkPremultiplyARGBInline(a, r, g, b);
         }
+    }
+}
+
+void SkColorMatrixFilter::filterSpan16(const uint16_t src[], int count,
+                                       uint16_t dst[]) const {
+    SkASSERT(fFlags & SkColorFilter::kHasFilter16_Flag);
+
+    Proc   proc = fProc;
+    const State& state = fState;
+    int32_t result[4];
+
+    if (NULL == proc) {
+        if (src != dst) {
+            memcpy(dst, src, count * sizeof(uint16_t));
+        }
+        return;
+    }
+
+    for (int i = 0; i < count; i++) {
+        uint16_t c = src[i];
+
+        // expand to 8bit components (since our matrix translate is 8bit biased
+        unsigned r = SkPacked16ToR32(c);
+        unsigned g = SkPacked16ToG32(c);
+        unsigned b = SkPacked16ToB32(c);
+
+        proc(state, r, g, b, 0, result);
+
+        r = pin(result[0], SK_R32_MASK);
+        g = pin(result[1], SK_G32_MASK);
+        b = pin(result[2], SK_B32_MASK);
+
+        // now packed it back down to 16bits (hmmm, could dither...)
+        dst[i] = SkPack888ToRGB16(r, g, b);
     }
 }