Revert of Move instanced index buffer creation to flush time

src/gpu/GrGpu.h

Index: src/gpu/GrGpu.h
diff --git a/src/gpu/GrGpu.h b/src/gpu/GrGpu.h
index 3903af6344bd015f37c9227dc8a5d7a787d5c8ce..b2dbec65fb1566b5a74083c8e32865cc0400f1ae 100644
--- a/src/gpu/GrGpu.h
+++ b/src/gpu/GrGpu.h
@@ -117,6 +117,34 @@
      * @return The index buffer if successful, otherwise NULL.
      */
     GrIndexBuffer* createIndexBuffer(size_t size, bool dynamic);
+
+    /**
+     * Creates an index buffer for instance drawing with a specific pattern.
+     *
+     * @param pattern     the pattern to repeat
+     * @param patternSize size in bytes of the pattern
+     * @param reps        number of times to repeat the pattern
+     * @param vertCount   number of vertices the pattern references
+     * @param dynamic     hints whether the data will be frequently changed
+     *                    by either GrIndexBuffer::map() or
+     *                    GrIndexBuffer::updateData().
+     *
+     * @return The index buffer if successful, otherwise NULL.
+     */
+    GrIndexBuffer* createInstancedIndexBuffer(const uint16_t* pattern,
+                                              int patternSize,
+                                              int reps,
+                                              int vertCount,
+                                              bool isDynamic = false);
+
+    /**
+     * Returns an index buffer that can be used to render quads.
+     * Six indices per quad: 0, 1, 2, 0, 2, 3, etc.
+     * The max number of quads can be queried using GrIndexBuffer::maxQuads().
+     * Draw with kTriangles_GrPrimitiveType
+     * @ return the quad index buffer
+     */
+    const GrIndexBuffer* getQuadIndexBuffer() const;
 
     /**
      * Resolves MSAA.
@@ -492,6 +520,8 @@
 
     ResetTimestamp                                                      fResetTimestamp;
     uint32_t                                                            fResetBits;
+    // these are mutable so they can be created on-demand
+    mutable GrIndexBuffer*                                              fQuadIndexBuffer;
     // To keep track that we always have at least as many debug marker adds as removes
     int                                                                 fGpuTraceMarkerCount;
     GrTraceMarkerSet                                                    fActiveTraceMarkers;