Turn off WEBGL_get_buffer_sub_data_async. (#849)

Author: Nikhil Thorat

src/environment.ts

@@ -174,6 +174,12 @@ function isFloatTextureReadPixelsEnabled(webGLVersion: number): boolean {
 }
 
 function isWebGLGetBufferSubDataAsyncExtensionEnabled(webGLVersion: number) {
+  // TODO(nsthorat): Remove this once we fix
+  // https://github.com/PAIR-code/deeplearnjs/issues/848
+  if (webGLVersion > 0) {
+    return false;
+  }
+
   if (webGLVersion !== 2) {
     return false;
   }

src/environment_test.ts

@@ -150,8 +150,10 @@ describe('WEBGL_GET_BUFFER_SUB_DATA_ASYNC_EXTENSION_ENABLED', () => {
 
     const env = new Environment(features);
 
+    // TODO(nsthorat): Expect true when we fix
+    // https://github.com/PAIR-code/deeplearnjs/issues/848
     expect(env.get('WEBGL_GET_BUFFER_SUB_DATA_ASYNC_EXTENSION_ENABLED'))
-        .toBe(true);
+        .toBe(false);
   });
 
   it('WebGL 1 disabled', () => {