Improve base64 decode and utf8 handling

html/js/overlay.js

@@ -0,0 +1,58 @@
+// ported from hterm.Terminal.prototype.showOverlay
+// https://chromium.googlesource.com/apps/libapps/+/master/hterm/js/hterm_terminal.js
+
+Terminal.prototype.showOverlay = function(msg, timeout) {
+    if (!this.overlayNode_) {
+        if (!this.element)
+            return;
+        this.overlayNode_ = document.createElement('div');
+        this.overlayNode_.style.cssText = (
+        'border-radius: 15px;' +
+        'font-size: xx-large;' +
+        'opacity: 0.75;' +
+        'padding: 0.2em 0.5em 0.2em 0.5em;' +
+        'position: absolute;' +
+        '-webkit-user-select: none;' +
+        '-webkit-transition: opacity 180ms ease-in;' +
+        '-moz-user-select: none;' +
+        '-moz-transition: opacity 180ms ease-in;');
+
+        this.overlayNode_.addEventListener('mousedown', function(e) {
+            e.preventDefault();
+            e.stopPropagation();
+        }, true);
+    }
+    this.overlayNode_.style.color = "#101010";
+    this.overlayNode_.style.backgroundColor = "#f0f0f0";
+
+    this.overlayNode_.textContent = msg;
+    this.overlayNode_.style.opacity = '0.75';
+
+    if (!this.overlayNode_.parentNode)
+        this.element.appendChild(this.overlayNode_);
+
+    var divSize = this.element.getBoundingClientRect();
+    var overlaySize = this.overlayNode_.getBoundingClientRect();
+
+    this.overlayNode_.style.top =
+        (divSize.height - overlaySize.height) / 2 + 'px';
+    this.overlayNode_.style.left = (divSize.width - overlaySize.width) / 2 + 'px';
+
+    var self = this;
+
+    if (this.overlayTimeout_)
+        clearTimeout(this.overlayTimeout_);
+
+    if (timeout === null)
+        return;
+
+    this.overlayTimeout_ = setTimeout(function() {
+        self.overlayNode_.style.opacity = '0';
+        self.overlayTimeout_ = setTimeout(function() {
+            if (self.overlayNode_.parentNode)
+                self.overlayNode_.parentNode.removeChild(self.overlayNode_);
+            self.overlayTimeout_ = null;
+            self.overlayNode_.style.opacity = '0.75';
+        }, 200);
+    }, timeout || 1500);
+};