Revert of Revert[2] of add ImageShader, sharing code with its Bitmap cousin

src/image/SkImageShader.cpp

Index: src/image/SkImageShader.cpp
diff --git a/src/image/SkImageShader.cpp b/src/image/SkImageShader.cpp
deleted file mode 100644
index 957081d20d03a87e5bd30c1ab35500fd57c9249f..0000000000000000000000000000000000000000
--- a/src/image/SkImageShader.cpp
+++ /dev/null
@@ -1,144 +0,0 @@
-/*
- * Copyright 2015 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#include "SkBitmapProcShader.h"
-#include "SkBitmapProvider.h"
-#include "SkImage_Base.h"
-#include "SkImageShader.h"
-#include "SkReadBuffer.h"
-#include "SkWriteBuffer.h"
-
-SkImageShader::SkImageShader(const SkImage* img, TileMode tmx, TileMode tmy, const SkMatrix* matrix)
-    : INHERITED(matrix)
-    , fImage(SkRef(img))
-    , fTileModeX(tmx)
-    , fTileModeY(tmy)
-{}
-
-SkFlattenable* SkImageShader::CreateProc(SkReadBuffer& buffer) {
-    const TileMode tx = (TileMode)buffer.readUInt();
-    const TileMode ty = (TileMode)buffer.readUInt();
-    SkMatrix matrix;
-    buffer.readMatrix(&matrix);
-    SkAutoTUnref<SkImage> img(buffer.readImage());
-    if (!img) {
-        return nullptr;
-    }
-    return new SkImageShader(img, tx, ty, &matrix);
-}
-
-void SkImageShader::flatten(SkWriteBuffer& buffer) const {
-    buffer.writeUInt(fTileModeX);
-    buffer.writeUInt(fTileModeY);
-    buffer.writeMatrix(this->getLocalMatrix());
-    buffer.writeImage(fImage);
-}
-
-bool SkImageShader::isOpaque() const {
-    return fImage->isOpaque();
-}
-
-size_t SkImageShader::contextSize() const {
-    return SkBitmapProcShader::ContextSize();
-}
-
-SkShader::Context* SkImageShader::onCreateContext(const ContextRec& rec, void* storage) const {
-    return SkBitmapProcShader::MakeContext(*this, fTileModeX, fTileModeY,
-                                           SkBitmapProvider(fImage), rec, storage);
-}
-
-SkShader* SkImageShader::Create(const SkImage* image, TileMode tx, TileMode ty,
-                                const SkMatrix* localMatrix) {
-    if (!image) {
-        return nullptr;
-    }
-    return new SkImageShader(image, tx, ty, localMatrix);
-}
-
-#ifndef SK_IGNORE_TO_STRING
-void SkImageShader::toString(SkString* str) const {
-    const char* gTileModeName[SkShader::kTileModeCount] = {
-        "clamp", "repeat", "mirror"
-    };
-
-    str->appendf("ImageShader: ((%s %s) ", gTileModeName[fTileModeX], gTileModeName[fTileModeY]);
-    fImage->toString(str);
-    this->INHERITED::toString(str);
-    str->append(")");
-}
-#endif
-
-///////////////////////////////////////////////////////////////////////////////////////////////////
-
-#if SK_SUPPORT_GPU
-
-#include "GrTextureAccess.h"
-#include "SkGr.h"
-#include "effects/GrSimpleTextureEffect.h"
-#include "effects/GrBicubicEffect.h"
-#include "effects/GrSimpleTextureEffect.h"
-
-const GrFragmentProcessor* SkImageShader::asFragmentProcessor(GrContext* context,
-                                                              const SkMatrix& viewM,
-                                                              const SkMatrix* localMatrix,
-                                                              SkFilterQuality filterQuality,
-                                                              GrProcessorDataManager* mgr) const {
-    SkMatrix matrix;
-    matrix.setIDiv(fImage->width(), fImage->height());
-
-    SkMatrix lmInverse;
-    if (!this->getLocalMatrix().invert(&lmInverse)) {
-        return nullptr;
-    }
-    if (localMatrix) {
-        SkMatrix inv;
-        if (!localMatrix->invert(&inv)) {
-            return nullptr;
-        }
-        lmInverse.postConcat(inv);
-    }
-    matrix.preConcat(lmInverse);
-
-    SkShader::TileMode tm[] = { fTileModeX, fTileModeY };
-
-    // Must set wrap and filter on the sampler before requesting a texture. In two places below
-    // we check the matrix scale factors to determine how to interpret the filter quality setting.
-    // This completely ignores the complexity of the drawVertices case where explicit local coords
-    // are provided by the caller.
-    bool doBicubic;
-    GrTextureParams::FilterMode textureFilterMode =
-    GrSkFilterQualityToGrFilterMode(filterQuality, viewM, this->getLocalMatrix(), &doBicubic);
-    GrTextureParams params(tm, textureFilterMode);
-
-    SkImageUsageType usageType;
-    if (kClamp_TileMode == fTileModeX && kClamp_TileMode == fTileModeY) {
-        usageType = kUntiled_SkImageUsageType;
-    } else if (GrTextureParams::kNone_FilterMode == textureFilterMode) {
-        usageType = kTiled_Unfiltered_SkImageUsageType;
-    } else {
-        usageType = kTiled_Filtered_SkImageUsageType;
-    }
-
-    SkAutoTUnref<GrTexture> texture(as_IB(fImage)->asTextureRef(context, usageType));
-    if (!texture) {
-        return nullptr;
-    }
-
-    SkAutoTUnref<GrFragmentProcessor> inner;
-    if (doBicubic) {
-        inner.reset(GrBicubicEffect::Create(mgr, texture, matrix, tm));
-    } else {
-        inner.reset(GrSimpleTextureEffect::Create(mgr, texture, matrix, params));
-    }
-
-    if (GrPixelConfigIsAlphaOnly(texture->config())) {
-        return SkRef(inner.get());
-    }
-    return GrFragmentProcessor::MulOuputByInputAlpha(inner);
-}
-
-#endif