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diff --git a/src/gpu/GrGeometryProcessor.h b/src/gpu/GrGeometryProcessor.h
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+++ b/src/gpu/GrGeometryProcessor.h
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+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrGeometryProcessor_DEFINED
+#define GrGeometryProcessor_DEFINED
+
+#include "GrProcessor.h"
+#include "GrShaderVar.h"
+
+/**
+ * A GrGeomteryProcessor is used to perform computation in the vertex shader and
+ * add support for custom vertex attributes. A GrGemeotryProcessor is typically
+ * tied to the code that does a specific type of high-level primitive rendering
+ * (e.g. anti-aliased circle rendering). The GrGeometryProcessor used for a draw is
+ * specified using GrDrawState. There can only be one geometry processor active for
+ * a draw. The custom vertex attributes required by the geometry processor must be
+ * added to the vertex attribute array specified on the GrDrawState.
+ * GrGeometryProcessor subclasses should be immutable after construction.
+ */
+class GrGeometryProcessor : public GrProcessor {
+public:
+    GrGeometryProcessor()
+        : fWillUseGeoShader(false) {}
+
+    virtual const GrBackendGeometryProcessorFactory& getFactory() const = 0;
+
+    /*
+     * This only has a max because GLProgramsTest needs to generate test arrays, and these have to
+     * be static
+     * TODO make this truly dynamic
+     */
+    static const int kMaxVertexAttribs = 2;
+    typedef SkTArray<GrShaderVar, true> VertexAttribArray;
+
+    const VertexAttribArray& getVertexAttribs() const { return fVertexAttribs; }
+
+    bool willUseGeoShader() const { return fWillUseGeoShader; }
+
+    /** Returns true if this and other processor conservatively draw identically. It can only return
+        true when the two prcoessors are of the same subclass (i.e. they return the same object from
+        from getFactory()).
+        A return value of true from isEqual() should not be used to test whether the processors
+        would generate the same shader code. To test for identical code generation use the
+        processors' keys computed by the GrBackendEffectFactory. */
+    bool isEqual(const GrGeometryProcessor& that) const {
+        if (&this->getFactory() != &that.getFactory() || !this->hasSameTextureAccesses(that)) {
+            return false;
+        }
+        return this->onIsEqual(that);
+    }
+
+protected:
+    /**
+     * Subclasses call this from their constructor to register vertex attributes (at most
+     * kMaxVertexAttribs). This must only be called from the constructor because GrProcessors are
+     * immutable.
+     */
+    const GrShaderVar& addVertexAttrib(const GrShaderVar& var) {
+        SkASSERT(fVertexAttribs.count() < kMaxVertexAttribs);
+        return fVertexAttribs.push_back(var);
+    }
+
+    void setWillUseGeoShader() { fWillUseGeoShader = true; }
+
+private:
+    virtual bool onIsEqual(const GrGeometryProcessor&) const = 0;
+
+    SkSTArray<kMaxVertexAttribs, GrShaderVar, true> fVertexAttribs;
+    bool fWillUseGeoShader;
+
+    typedef GrProcessor INHERITED;
+};
+
+#endif