Option to send photos as high quality

ts/test-electron/util/canvasToBlob_test.ts

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+// Copyright 2021 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { assert } from 'chai';
+
+import { canvasToBlob } from '../../util/canvasToBlob';
+
+describe('canvasToBlob', () => {
+  it('converts a canvas to an Blob', async () => {
+    const canvas = document.createElement('canvas');
+    canvas.width = 100;
+    canvas.height = 200;
+
+    const context = canvas.getContext('2d');
+    if (!context) {
+      throw new Error('Test setup error: cannot get canvas rendering context');
+    }
+    context.fillStyle = '#ff9900';
+    context.fillRect(10, 10, 20, 20);
+
+    const result = await canvasToBlob(canvas);
+
+    // These are just smoke tests.
+    assert.instanceOf(result, Blob);
+    assert.isAtLeast(result.size, 50);
+  });
+});