Use node-pre-gyp again to cache grpc binary

So that we don't have to build grpc c++ library each time the npm
package is installed. The binary is uploaded to releases in github
repo using node-pre-gyp-github tool and it is fetched by node-pre-gyp
from there.

packages/grpc-native-core/binding.gyp

@@ -1151,6 +1151,17 @@
         "ares",
         "address_sorting"
       ]
+    },
+    {
+      "target_name": "action_after_build",
+      "type": "none",
+      "dependencies": [ "<(module_name)" ],
+      "copies": [
+        {
+          "files": [ "<(PRODUCT_DIR)/<(module_name).node"],
+          "destination": "<(module_path)"
+        }
+      ]
     }
   ]
 }

packages/grpc-native-core/package.json

@@ -1,6 +1,6 @@
 {
   "name": "grpc-uds",
-  "version": "0.1.4",
+  "version": "0.1.6",
   "author": "Jan Kryl & Google Inc.",
   "description": "TEMPORARY and EXPERIMENTAL gRPC Library for Node supporting Unix Domain Sockets",
   "homepage": "https://grpc.io/",
@@ -19,15 +19,20 @@
     "lib": "src"
   },
   "scripts": {
-    "build": "node-gyp rebuild",
+    "build": "node-pre-gyp build",
+    "electron-build": "node-pre-gyp configure build --runtime=electron --disturl=https://atom.io/download/atom-shell",
     "coverage": "istanbul cover ./node_modules/.bin/_mocha test",
-    "install": "node-gyp rebuild",
+    "install": "node-pre-gyp install --fallback-to-build --library=static_library",
     "prepack": "git submodule update --init --recursive && npm install"
   },
+  "bundledDependencies": [
+    "node-pre-gyp"
+  ],
   "dependencies": {
     "lodash.camelcase": "^4.3.0",
     "lodash.clone": "^4.5.0",
     "nan": "^2.13.2",
+    "node-pre-gyp": "^0.13.0",
     "protobufjs": "^5.0.3"
   },
   "devDependencies": {
@@ -44,6 +49,13 @@
   "engines": {
     "node": ">=4"
   },
+  "binary": {
+    "module_name": "grpc_node",
+    "module_path": "src/node/extension_binary/{node_abi}-{platform}-{arch}-{libc}",
+    "host": "https://github.com/jkryl/grpc-node/releases/download/",
+    "remote_path": "{version}",
+    "package_name": "{node_abi}-{platform}-{arch}-{libc}.tar.gz"
+  },
   "files": [
     "LICENSE",
     "README.md",

packages/grpc-native-core/src/grpc_extension.js

@@ -23,15 +23,40 @@
 
 'use strict';
 
+var binary = require('node-pre-gyp/lib/pre-binding');
+var path = require('path');
+var binding_path =
+    binary.find(path.resolve(path.join(__dirname, '../package.json')));
 var binding;
 try {
-  binding = require('../build/Release/grpc_node.node');
+  binding = require(binding_path);
 } catch (e) {
+  let fs = require('fs');
+  let searchPath = path.dirname(path.dirname(binding_path));
+  let searchName = path.basename(path.dirname(binding_path));
+  let foundNames;
+  try {
+    foundNames = fs.readdirSync(searchPath);
+  } catch (readDirError) {
     let message = `The gRPC binary module was not installed. This may be fixed by running "npm rebuild"
 Original error: ${e.message}`;
     let error = new Error(message);
     error.code = e.code;
     throw error;
+  }
+  if (foundNames.indexOf(searchName) === -1) {
+    let message = `Failed to load gRPC binary module because it was not installed for the current system
+Expected directory: ${searchName}
+Found: [${foundNames.join(', ')}]
+This problem can often be fixed by running "npm rebuild" on the current system
+Original error: ${e.message}`;
+    let error = new Error(message);
+    error.code = e.code;
+    throw error;
+  } else {
+    e.message = `Failed to load ${binding_path}. ${e.message}`;
+    throw e;
+  }
 }
 
 module.exports = binding;