[Reland] Relocate shaders to own dir

Consolidate all shader impls under src/shaders/.

(reland of https://skia-review.googlesource.com/c/17927/)

Change-Id: I7918bdc1aafe842ed194412ba95b9ae53a2ec1d7
Reviewed-on: https://skia-review.googlesource.com/18146
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@chromium.org>

1 files changed, 41 insertions, 0 deletions

diff --git a/src/shaders/SkEmptyShader.h b/src/shaders/SkEmptyShader.h
new file mode 100644
index 0000000000..d7187c4edf
--- /dev/null
+++ b/src/shaders/SkEmptyShader.h
@@ -0,0 +1,41 @@
+/*
+ * Copyright 2011 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkEmptyShader_DEFINED
+#define SkEmptyShader_DEFINED
+
+#include "SkShaderBase.h"
+
+// TODO: move this to private, as there is a public factory on SkShader
+
+/**
+ *  \class SkEmptyShader
+ *  A Shader that always draws nothing. Its createContext always returns nullptr.
+ */
+class SkEmptyShader : public SkShaderBase {
+public:
+    SkEmptyShader() {}
+
+    SK_TO_STRING_OVERRIDE()
+    SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkEmptyShader)
+
+protected:
+    Context* onMakeContext(const ContextRec&, SkArenaAlloc*) const override {
+        return nullptr;
+    }
+
+    void flatten(SkWriteBuffer& buffer) const override {
+        // Do nothing.
+        // We just don't want to fall through to SkShader::flatten(),
+        // which will write data we don't care to serialize or decode.
+    }
+
+private:
+    typedef SkShaderBase INHERITED;
+};
+
+#endif