Implement GL support for buffer textures

src/gpu/gl/GrGLGpu.h

Index: src/gpu/gl/GrGLGpu.h
diff --git a/src/gpu/gl/GrGLGpu.h b/src/gpu/gl/GrGLGpu.h
index e365601e1fddada89ca9ba9817eaf722f13ba065..a3e457ce9304195cd62352fb5ef06a1ff50a0f1c 100644
--- a/src/gpu/gl/GrGLGpu.h
+++ b/src/gpu/gl/GrGLGpu.h
@@ -58,9 +58,6 @@ public:
 
     void discard(GrRenderTarget*) override;
 
-    // Used by GrGLProgram to configure OpenGL state.
-    void bindTexture(int unitIdx, const GrTextureParams& params, GrGLTexture* texture);
-
     bool onGetReadPixelsInfo(GrSurface* srcSurface, int readWidth, int readHeight, size_t rowBytes,
                              GrPixelConfig readConfig, DrawPreference*,
                              ReadPixelTempDrawInfo*) override;
@@ -244,6 +241,12 @@ private:
 
     bool hasExtension(const char* ext) const { return fGLContext->hasExtension(ext); }
 
+    // binds a texture to its target, on the specified texture unit
+    void bindTexture(int unitIdx, GrGLTexture*);
+
+    // binds a texture and flushes texture params to it
+    void flushTexture(int unitIdx, const GrTextureParams& params, GrGLTexture* texture);
+
     void copySurfaceAsDraw(GrSurface* dst,
                            GrSurface* src,
                            const SkIRect& srcRect,