diff -r 000000000000 -r 6474c204b198 gfx/angle/src/libGLESv2/renderer/IndexRangeCache.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/angle/src/libGLESv2/renderer/IndexRangeCache.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,58 @@
+//
+// Copyright (c) 2013 The ANGLE Project Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+
+// IndexRangeCache.h: Defines the rx::IndexRangeCache class which stores information about
+// ranges of indices.
+
+#ifndef LIBGLESV2_RENDERER_INDEXRANGECACHE_H_
+#define LIBGLESV2_RENDERER_INDEXRANGECACHE_H_
+
+#include "common/angleutils.h"
+
+namespace rx
+{
+
+class IndexRangeCache
+{
+  public:
+    void addRange(GLenum type, intptr_t offset, GLsizei count, unsigned int minIdx, unsigned int maxIdx, 
+                  unsigned int streamOffset);
+    bool findRange(GLenum type, intptr_t offset, GLsizei count, unsigned int *outMinIndex,
+                   unsigned int *outMaxIndex, unsigned int *outStreamOffset) const;
+
+    void invalidateRange(unsigned int offset, unsigned int size);
+    void clear();
+
+  private:
+    struct IndexRange
+    {
+        GLenum type;
+        intptr_t offset;
+        GLsizei count;
+
+        IndexRange();
+        IndexRange(GLenum type, intptr_t offset, GLsizei count);
+
+        bool operator<(const IndexRange& rhs) const;
+    };
+
+    struct IndexBounds
+    {
+        unsigned int minIndex;
+        unsigned int maxIndex;
+        unsigned int streamOffset;
+
+        IndexBounds();
+        IndexBounds(unsigned int minIdx, unsigned int maxIdx, unsigned int offset);
+    };
+
+    typedef std::map<IndexRange, IndexBounds> IndexRangeMap;
+    IndexRangeMap mIndexRangeCache;
+};
+
+}
+
+#endif LIBGLESV2_RENDERER_INDEXRANGECACHE_H