Revert "Relocate shaders to own dir"

This reverts commit fabe0b26d05624ce7374f6ca89bd66df6142534e.

Reason for revert: Last android roll failed with "external/skia/src/effects/SkGaussianEdgeShader.h:11:10: fatal error: 'SkShaderBase.h' file not found"

Original change's description:
> Relocate shaders to own dir
> 
> Consolidate all shader impls under src/shaders/.
> 
> Change-Id: I450e37541214704c1ad9e379d9d753b7cc62fac3
> Reviewed-on: https://skia-review.googlesource.com/17927
> Commit-Queue: Florin Malita <fmalita@chromium.org>
> Reviewed-by: Herb Derby <herb@google.com>
> 

TBR=mtklein@google.com,herb@google.com,fmalita@chromium.org,reed@google.com
No-Presubmit: true
No-Tree-Checks: true
No-Try: true

Change-Id: Idbb2b75053969df1dad9d8ce0217cd39189b9ddb
Reviewed-on: https://skia-review.googlesource.com/18020
Reviewed-by: Stan Iliev <stani@google.com>
Commit-Queue: Stan Iliev <stani@google.com>

1 files changed, 87 insertions, 0 deletions

diff --git a/src/effects/gradients/SkLinearGradient.h b/src/effects/gradients/SkLinearGradient.h
new file mode 100644
index 0000000000..19a965c7bb
--- /dev/null
+++ b/src/effects/gradients/SkLinearGradient.h
@@ -0,0 +1,87 @@
+/*
+ * Copyright 2012 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkLinearGradient_DEFINED
+#define SkLinearGradient_DEFINED
+
+#include "SkGradientShaderPriv.h"
+#include "SkNx.h"
+
+struct Sk4fStorage {
+    float fArray[4];
+
+    operator Sk4f() const {
+        return Sk4f::Load(fArray);
+    }
+
+    Sk4fStorage& operator=(const Sk4f& src) {
+        src.store(fArray);
+        return *this;
+    }
+};
+
+class SkLinearGradient : public SkGradientShaderBase {
+public:
+    enum {
+        // Temp flag for testing the 4f impl.
+        kForce4fContext_PrivateFlag     = 1 << 7,
+    };
+
+    SkLinearGradient(const SkPoint pts[2], const Descriptor&);
+
+    class LinearGradientContext : public SkGradientShaderBase::GradientShaderBaseContext {
+    public:
+        LinearGradientContext(const SkLinearGradient&, const ContextRec&);
+
+        void shadeSpan(int x, int y, SkPMColor dstC[], int count) override;
+
+        struct Rec {
+            Sk4fStorage fColor;
+            float       fPos;
+            float       fPosScale;
+        };
+    private:
+        SkTDArray<Rec>  fRecs;
+        bool            fApplyAlphaAfterInterp;
+
+        void shade4_clamp(int x, int y, SkPMColor dstC[], int count);
+        template <bool, bool> void shade4_dx_clamp(SkPMColor dstC[], int count, float fx, float dx,
+                                                   float invDx, const float dither[2]);
+
+        typedef SkGradientShaderBase::GradientShaderBaseContext INHERITED;
+    };
+
+    GradientType asAGradient(GradientInfo* info) const override;
+#if SK_SUPPORT_GPU
+    sk_sp<GrFragmentProcessor> asFragmentProcessor(const AsFPArgs&) const override;
+#endif
+
+    SK_TO_STRING_OVERRIDE()
+    SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkLinearGradient)
+
+protected:
+    SkLinearGradient(SkReadBuffer& buffer);
+    void flatten(SkWriteBuffer& buffer) const override;
+    Context* onMakeContext(const ContextRec&, SkArenaAlloc*) const override;
+
+    bool adjustMatrixAndAppendStages(SkArenaAlloc* alloc,
+                                     SkMatrix* matrix,
+                                     SkRasterPipeline* p) const final;
+
+
+    sk_sp<SkShader> onMakeColorSpace(SkColorSpaceXformer* xformer) const override;
+
+private:
+    class LinearGradient4fContext;
+
+    friend class SkGradientShader;
+    typedef SkGradientShaderBase INHERITED;
+    const SkPoint fStart;
+    const SkPoint fEnd;
+};
+
+#endif