Add GL indirect drawing APIs

src/gpu/gl/GrGLInterface.cpp

Index: src/gpu/gl/GrGLInterface.cpp
diff --git a/src/gpu/gl/GrGLInterface.cpp b/src/gpu/gl/GrGLInterface.cpp
index b8d7db6b2e513bcfe3c16b778cef36601954893a..925f081b342bb733001829bc9edb51719292de5b 100644
--- a/src/gpu/gl/GrGLInterface.cpp
+++ b/src/gpu/gl/GrGLInterface.cpp
@@ -579,6 +579,22 @@ bool GrGLInterface::validate() const {
         }    
     }
 
+    if ((kGL_GrGLStandard == fStandard && glVer >= GR_GL_VER(4,3)) ||
+        (kGLES_GrGLStandard == fStandard && glVer >= GR_GL_VER(3,1))) {
+        if (NULL == fFunctions.fDrawArraysIndirect ||
+            NULL == fFunctions.fDrawElementsIndirect) {
+            RETURN_FALSE_INTERFACE
+        }
+    }
+
+    if ((kGL_GrGLStandard == fStandard && glVer >= GR_GL_VER(4,3)) ||
+        (kGLES_GrGLStandard == fStandard && fExtensions.has("GL_EXT_multi_draw_indirect"))) {
+        if (NULL == fFunctions.fMultiDrawArraysIndirect ||
+            NULL == fFunctions.fMultiDrawElementsIndirect) {
+            RETURN_FALSE_INTERFACE
+        }
+    }
+
     if (fExtensions.has("GL_NV_bindless_texture")) {
         if (nullptr == fFunctions.fGetTextureHandle ||
             nullptr == fFunctions.fGetTextureSamplerHandle ||