Revert of Revert of remove colorfilter native-565 support. complicating w/ no real value. (patchset #1 id:1 of https://codereview.chromium.org/1022673007/)

Reason for revert:
fix for chrome has landed...

Original issue's description:
> Revert of remove colorfilter native-565 support. complicating w/ no real value. (patchset #2 id:20001 of https://codereview.chromium.org/1015533011/)
>
> Reason for revert:
> skia/ext/benchmarking_canvas.cc references HasFilter16 :(
>
> Original issue's description:
> > remove colorfilter native-565 support. complicating w/ no real value.
> >
> > BUG=skia:
> > TBR=
> >
> > Committed: https://skia.googlesource.com/skia/+/2151353d161fe389cdc0db62cfe1932c7680f710
>
> TBR=reed@chromium.org
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=skia:
>
> Committed: https://skia.googlesource.com/skia/+/92b47c49016749249ff8521e424c4373b4a74241

TBR=reed@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review URL: https://codereview.chromium.org/1016103004

5 files changed, 15 insertions, 113 deletions

diff --git a/src/core/SkColorFilter.cpp b/src/core/SkColorFilter.cpp
index 0a9cd93e34..45950ad0b5 100644
--- a/src/core/SkColorFilter.cpp
+++ b/src/core/SkColorFilter.cpp
@@ -22,15 +22,6 @@ bool SkColorFilter::asComponentTable(SkBitmap*) const {
     return false;
 }
 
-void SkColorFilter::filterSpan16(const uint16_t s[], int count, uint16_t d[]) const {
-    SkASSERT(this->getFlags() & SkColorFilter::kHasFilter16_Flag);
-    SkDEBUGFAIL("missing implementation of SkColorFilter::filterSpan16");
-
-    if (d != s) {
-        memcpy(d, s, count * sizeof(uint16_t));
-    }
-}
-
 SkColor SkColorFilter::filterColor(SkColor c) const {
     SkPMColor dst, src = SkPreMultiplyColor(c);
     this->filterSpan(&src, 1, &dst);
@@ -61,12 +52,6 @@ public:
         fOuter->filterSpan(result, count, result);
     }
     
-    void filterSpan16(const uint16_t shader[], int count, uint16_t result[]) const SK_OVERRIDE {
-        SkASSERT(this->getFlags() & kHasFilter16_Flag);
-        fInner->filterSpan16(shader, count, result);
-        fOuter->filterSpan16(result, count, result);
-    }
-    
 #ifndef SK_IGNORE_TO_STRING
     void toString(SkString* str) const SK_OVERRIDE {
         SkString outerS, innerS;
diff --git a/src/core/SkFilterShader.cpp b/src/core/SkFilterShader.cpp
index 48c4b8b477..a10a7c9d77 100644
--- a/src/core/SkFilterShader.cpp
+++ b/src/core/SkFilterShader.cpp
@@ -46,13 +46,12 @@ uint32_t SkFilterShader::FilterShaderContext::getFlags() const {
     uint32_t shaderF = fShaderContext->getFlags();
     uint32_t filterF = filterShader.fFilter->getFlags();
 
-    // if the filter doesn't support 16bit, clear the matching bit in the shader
-    if (!(filterF & SkColorFilter::kHasFilter16_Flag)) {
-        shaderF &= ~SkShader::kHasSpan16_Flag;
-    }
+    // filters don't support 16bit, so clear the matching bit in the shader
+    shaderF &= ~SkShader::kHasSpan16_Flag;
+
     // if the filter might change alpha, clear the opaque flag in the shader
     if (!(filterF & SkColorFilter::kAlphaUnchanged_Flag)) {
-        shaderF &= ~(SkShader::kOpaqueAlpha_Flag | SkShader::kHasSpan16_Flag);
+        shaderF &= ~SkShader::kOpaqueAlpha_Flag;
     }
     return shaderF;
 }
@@ -87,16 +86,6 @@ void SkFilterShader::FilterShaderContext::shadeSpan(int x, int y, SkPMColor resu
     filterShader.fFilter->filterSpan(result, count, result);
 }
 
-void SkFilterShader::FilterShaderContext::shadeSpan16(int x, int y, uint16_t result[], int count) {
-    const SkFilterShader& filterShader = static_cast<const SkFilterShader&>(fShader);
-
-    SkASSERT(fShaderContext->getFlags() & SkShader::kHasSpan16_Flag);
-    SkASSERT(filterShader.fFilter->getFlags() & SkColorFilter::kHasFilter16_Flag);
-
-    fShaderContext->shadeSpan16(x, y, result, count);
-    filterShader.fFilter->filterSpan16(result, count, result);
-}
-
 #ifndef SK_IGNORE_TO_STRING
 void SkFilterShader::toString(SkString* str) const {
     str->append("SkFilterShader: (");
diff --git a/src/core/SkFilterShader.h b/src/core/SkFilterShader.h
index dca9567e66..65291c8f39 100644
--- a/src/core/SkFilterShader.h
+++ b/src/core/SkFilterShader.h
@@ -28,7 +28,6 @@ public:
         uint32_t getFlags() const SK_OVERRIDE;
 
         void shadeSpan(int x, int y, SkPMColor[], int count) SK_OVERRIDE;
-        void shadeSpan16(int x, int y, uint16_t[], int count) SK_OVERRIDE;
 
         void set3DMask(const SkMask* mask) SK_OVERRIDE {
             // forward to our proxy
diff --git a/src/effects/SkColorFilters.cpp b/src/effects/SkColorFilters.cpp
index 8bcd0ebc5d..8c021e452b 100644
--- a/src/effects/SkColorFilters.cpp
+++ b/src/effects/SkColorFilters.cpp
@@ -27,7 +27,14 @@ bool SkModeColorFilter::asColorMode(SkColor* color, SkXfermode::Mode* mode) cons
 }
 
 uint32_t SkModeColorFilter::getFlags() const {
-    return fProc16 ? (kAlphaUnchanged_Flag | kHasFilter16_Flag) : 0;
+    switch (fMode) {
+        case SkXfermode::kDst_Mode:      //!< [Da, Dc]
+        case SkXfermode::kSrcATop_Mode:  //!< [Da, Sc * Da + (1 - Sa) * Dc]
+            return kAlphaUnchanged_Flag;
+        default:
+            break;
+    }
+    return 0;
 }
 
 void SkModeColorFilter::filterSpan(const SkPMColor shader[], int count, SkPMColor result[]) const {
@@ -39,16 +46,6 @@ void SkModeColorFilter::filterSpan(const SkPMColor shader[], int count, SkPMColo
     }
 }
 
-void SkModeColorFilter::filterSpan16(const uint16_t shader[], int count, uint16_t result[]) const {
-    SkASSERT(this->getFlags() & kHasFilter16_Flag);
-    
-    SkPMColor        color = fPMColor;
-    SkXfermodeProc16 proc16 = fProc16;
-    
-    for (int i = 0; i < count; i++) {
-        result[i] = proc16(color, shader[i]);
-    }
-}
 void SkModeColorFilter::flatten(SkWriteBuffer& buffer) const {
     buffer.writeColor(fColor);
     buffer.writeUInt(fMode);
@@ -57,7 +54,6 @@ void SkModeColorFilter::flatten(SkWriteBuffer& buffer) const {
 void SkModeColorFilter::updateCache() {
     fPMColor = SkPreMultiplyColor(fColor);
     fProc = SkXfermode::GetProc(fMode);
-    fProc16 = SkXfermode::GetProc16(fMode, fColor);
 }
 
 SkFlattenable* SkModeColorFilter::CreateProc(SkReadBuffer& buffer) {
@@ -388,25 +384,10 @@ class Src_SkModeColorFilter : public SkModeColorFilter {
 public:
     Src_SkModeColorFilter(SkColor color) : INHERITED(color, SkXfermode::kSrc_Mode) {}
 
-    uint32_t getFlags() const SK_OVERRIDE {
-        if (SkGetPackedA32(this->getPMColor()) == 0xFF) {
-            return kAlphaUnchanged_Flag | kHasFilter16_Flag;
-        } else {
-            return 0;
-        }
-    }
-
-    virtual void filterSpan(const SkPMColor shader[], int count,
-                            SkPMColor result[]) const SK_OVERRIDE {
+    void filterSpan(const SkPMColor shader[], int count, SkPMColor result[]) const SK_OVERRIDE {
         sk_memset32(result, this->getPMColor(), count);
     }
 
-    virtual void filterSpan16(const uint16_t shader[], int count,
-                              uint16_t result[]) const SK_OVERRIDE {
-        SkASSERT(this->getFlags() & kHasFilter16_Flag);
-        sk_memset16(result, SkPixel32ToPixel16(this->getPMColor()), count);
-    }
-
 private:
     typedef SkModeColorFilter INHERITED;
 };
@@ -418,25 +399,10 @@ public:
         fColor32Proc = SkBlitRow::ColorProcFactory();
     }
 
-    uint32_t getFlags() const SK_OVERRIDE {
-        if (SkGetPackedA32(this->getPMColor()) == 0xFF) {
-            return kAlphaUnchanged_Flag | kHasFilter16_Flag;
-        } else {
-            return 0;
-        }
-    }
-
-    virtual void filterSpan(const SkPMColor shader[], int count,
-                            SkPMColor result[]) const SK_OVERRIDE {
+    void filterSpan(const SkPMColor shader[], int count, SkPMColor result[]) const SK_OVERRIDE {
         fColor32Proc(result, shader, count, this->getPMColor());
     }
 
-    virtual void filterSpan16(const uint16_t shader[], int count,
-                              uint16_t result[]) const SK_OVERRIDE {
-        SkASSERT(this->getFlags() & kHasFilter16_Flag);
-        sk_memset16(result, SkPixel32ToPixel16(this->getPMColor()), count);
-    }
-
 private:
 
     SkBlitRow::ColorProc fColor32Proc;
diff --git a/src/effects/SkColorMatrixFilter.cpp b/src/effects/SkColorMatrixFilter.cpp
index 04c00c951f..3bdda61187 100644
--- a/src/effects/SkColorMatrixFilter.cpp
+++ b/src/effects/SkColorMatrixFilter.cpp
@@ -139,9 +139,6 @@ static void Add16(const SkColorMatrixFilter::State& state,
     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) {
@@ -183,7 +180,7 @@ void SkColorMatrixFilter::initState(const SkScalar* SK_RESTRICT src) {
         fProc = shiftIs16 ? General16 : General;
         fFlags = changesAlpha ? 0 : SkColorFilter::kAlphaUnchanged_Flag;
     } else {
-        fFlags = kNO_ALPHA_FLAGS;
+        fFlags = SkColorFilter::kAlphaUnchanged_Flag;
 
         int32_t needsScale = (array[SkColorMatrix::kR_Scale] - one) |
                              (array[SkColorMatrix::kG_Scale] - one) |
@@ -365,40 +362,6 @@ void SkColorMatrixFilter::filterSpan(const SkPMColor src[], int count, SkPMColor
     }
 }
 
-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);
-    }
-}
-
 ///////////////////////////////////////////////////////////////////////////////
 
 void SkColorMatrixFilter::flatten(SkWriteBuffer& buffer) const {