Add support for vertex and geometry shader textures

src/gpu/gl/GrGLTexture.cpp

Index: src/gpu/gl/GrGLTexture.cpp
diff --git a/src/gpu/gl/GrGLTexture.cpp b/src/gpu/gl/GrGLTexture.cpp
index e05006c46e986c914a720be71fc84b3c84acc3a3..a27140ed9e0d11d977f1a32485f78e8d7ddbbd12 100644
--- a/src/gpu/gl/GrGLTexture.cpp
+++ b/src/gpu/gl/GrGLTexture.cpp
@@ -64,6 +64,17 @@ void GrGLTexture::onAbandon() {
     INHERITED::onAbandon();
 }
 
+GrSLType GrGLTexture::getSamplerType() const {
+    if (GR_GL_TEXTURE_EXTERNAL == fInfo.fTarget) {
+        return kSamplerExternal_GrSLType;
+    } else if (GR_GL_TEXTURE_RECTANGLE == fInfo.fTarget) {
+        return kSampler2DRect_GrSLType;
+    } else {
+        SkASSERT(GR_GL_TEXTURE_2D == fInfo.fTarget);
+        return kSampler2D_GrSLType;
+    }
+}
+
 GrBackendObject GrGLTexture::getTextureHandle() const {
 #ifdef SK_IGNORE_GL_TEXTURE_TARGET
     return static_cast<GrBackendObject>(this->textureID());