feat(browsercontext): implement BrowserContext.overridePermissions (#3159)

Introduce an API to manage permissions per browser context:
- BrowserContext.overridePermissions(origin, permissions)
- BrowserContext.clearPermissionOverrides()

Fixes #846.

lib/Browser.js

@@ -37,11 +37,11 @@ class Browser extends EventEmitter {
     this._connection = connection;
     this._closeCallback = closeCallback || new Function();
 
-    this._defaultContext = new BrowserContext(this, null);
+    this._defaultContext = new BrowserContext(this._connection, this, null);
     /** @type {Map<string, BrowserContext>} */
     this._contexts = new Map();
     for (const contextId of contextIds)
-      this._contexts.set(contextId, new BrowserContext(this, contextId));
+      this._contexts.set(contextId, new BrowserContext(this._connection, this, contextId));
 
     /** @type {Map<string, Target>} */
     this._targets = new Map();
@@ -65,7 +65,7 @@ class Browser extends EventEmitter {
    */
   async createIncognitoBrowserContext() {
     const {browserContextId} = await this._connection.send('Target.createBrowserContext');
-    const context = new BrowserContext(this, browserContextId);
+    const context = new BrowserContext(this._connection, this, browserContextId);
     this._contexts.set(browserContextId, context);
     return context;
   }
@@ -77,6 +77,13 @@ class Browser extends EventEmitter {
     return [this._defaultContext, ...Array.from(this._contexts.values())];
   }
 
+  /**
+   * @return {!BrowserContext}
+   */
+  defaultBrowserContext() {
+    return this._defaultContext;
+  }
+
   /**
    * @param {?string} contextId
    */
@@ -231,11 +238,13 @@ Browser.Events = {
 
 class BrowserContext extends EventEmitter {
   /**
+   * @param {!Puppeteer.Connection} connection
    * @param {!Browser} browser
    * @param {?string} contextId
    */
-  constructor(browser, contextId) {
+  constructor(connection, browser, contextId) {
     super();
+    this._connection = connection;
     this._browser = browser;
     this._id = contextId;
   }
@@ -266,6 +275,43 @@ class BrowserContext extends EventEmitter {
     return !!this._id;
   }
 
+  /**
+   * @param {string} origin
+   * @param {!Array<string>} permissions
+   */
+  async overridePermissions(origin, permissions) {
+    const webPermissionToProtocol = new Map([
+      ['geolocation', 'geolocation'],
+      ['midi', 'midi'],
+      ['notifications', 'notifications'],
+      ['push', 'push'],
+      ['camera', 'videoCapture'],
+      ['microphone', 'audioCapture'],
+      ['background-sync', 'backgroundSync'],
+      ['ambient-light-sensor', 'sensors'],
+      ['accelerometer', 'sensors'],
+      ['gyroscope', 'sensors'],
+      ['magnetometer', 'sensors'],
+      ['accessibility-events', 'accessibilityEvents'],
+      ['clipboard-read', 'clipboardRead'],
+      ['clipboard-write', 'clipboardWrite'],
+      ['payment-handler', 'paymentHandler'],
+      // chrome-specific permissions we have.
+      ['midi-sysex', 'midiSysex'],
+    ]);
+    permissions = permissions.map(permission => {
+      const protocolPermission = webPermissionToProtocol.get(permission);
+      if (!protocolPermission)
+        throw new Error('Unknown permission: ' + permission);
+      return protocolPermission;
+    });
+    await this._connection.send('Browser.grantPermissions', {origin, browserContextId: this._id || undefined, permissions});
+  }
+
+  async clearPermissionOverrides() {
+    await this._connection.send('Browser.resetPermissions', {browserContextId: this._id || undefined});
+  }
+
   /**
    * @return {!Promise<!Puppeteer.Page>}
    */