Remove pointless Display.clear()

It served no meaningful purpose and it had bugs. So let's remove it
rather than try to fix it.

kasmweb/core/display.js

@@ -60,8 +60,6 @@ export default class Display {
 
         Log.Debug("User Agent: " + navigator.userAgent);
 
-        this.clear();
-
         // Check canvas features
         if (!('createImageData' in this._drawCtx)) {
             throw new Error("Canvas does not support createImageData");
@@ -301,12 +299,6 @@ export default class Display {
         }
     }
 
-    clear() {
-        this.resize(240, 20);
-        this._drawCtx.clearRect(0, 0, this._fb_width, this._fb_height);
-        this.flip();
-    }
-
     pending() {
         return this._renderQ.length > 0;
     }

kasmweb/core/rfb.js

@@ -193,7 +193,6 @@ export default class RFB extends EventTargetMixin {
             throw exc;
         }
         this._display.onflush = this._onFlush.bind(this);
-        this._display.clear();
 
         this._keyboard = new Keyboard(this._canvas);
         this._keyboard.onkeyevent = this._handleKeyEvent.bind(this);

kasmweb/docs/API-internal.md

@@ -99,7 +99,6 @@ None
 | absY               | (y)                                                     | Return Y relative to the remote display
 | resize             | (width, height)                                         | Set width and height
 | flip               | (from_queue)                                            | Update the visible canvas with the contents of the rendering canvas
-| clear              | ()                                                      | Clear the display
 | pending            | ()                                                      | Check if there are waiting items in the render queue
 | flush              | ()                                                      | Resume processing the render queue unless it's empty
 | fillRect           | (x, y, width, height, color, from_queue)                | Draw a filled in rectangle

kasmweb/tests/test.display.js

@@ -269,15 +269,6 @@ describe('Display/Canvas Helper', function () {
             display.resize(4, 4);
         });
 
-        it('should clear the screen on #clear', function () {
-            display.fillRect(0, 0, 4, 4, [0x00, 0x00, 0xff]);
-            display.clear();
-            display.resize(4, 4);
-            const empty = [];
-            for (let i = 0; i < 4 * display._fb_width * display._fb_height; i++) { empty[i] = 0; }
-            expect(display).to.have.displayed(new Uint8Array(empty));
-        });
-
         it('should not draw directly on the target canvas', function () {
             display.fillRect(0, 0, 4, 4, [0, 0, 0xff]);
             display.flip();