Merge remote-tracking branch 'ups/master' into fast_setTheme

addons/xterm-addon-webgl/src/atlas/WebglCharAtlas.ts

@@ -110,7 +110,10 @@ export class WebglCharAtlas implements IDisposable {
     this._tmpCanvas = document.createElement('canvas');
     this._tmpCanvas.width = this._config.scaledCellWidth * 4 + TMP_CANVAS_GLYPH_PADDING * 2;
     this._tmpCanvas.height = this._config.scaledCellHeight + TMP_CANVAS_GLYPH_PADDING * 2;
-    this._tmpCtx = throwIfFalsy(this._tmpCanvas.getContext('2d', { alpha: this._config.allowTransparency }));
+    this._tmpCtx = throwIfFalsy(this._tmpCanvas.getContext('2d', {
+      alpha: this._config.allowTransparency,
+      willReadFrequently: true
+    }));
   }
 
   public dispose(): void {

src/common/Color.ts

@@ -110,7 +110,9 @@ export namespace css {
     const canvas = document.createElement('canvas');
     canvas.width = 1;
     canvas.height = 1;
-    const ctx = canvas.getContext('2d');
+    const ctx = canvas.getContext('2d', {
+      willReadFrequently: true
+    });
     if (ctx) {
       $ctx = ctx;
       $ctx.globalCompositeOperation = 'copy';