Remove getAjaxVersion().

It was very specific to prototype, which has a very low adoption rate
these days.

/**
 * testRequestClientTypes method
 *
 * @return void
 */
	public function testRequestClientTypes() {
		$this->RequestHandler->request->env('HTTP_X_PROTOTYPE_VERSION', '1.5');
		$this->assertEquals('1.5', $this->RequestHandler->getAjaxVersion());

		$this->RequestHandler->request->env('HTTP_X_REQUESTED_WITH', false);
		$this->RequestHandler->request->env('HTTP_X_PROTOTYPE_VERSION', false);
		$this->assertFalse($this->RequestHandler->getAjaxVersion());
	}

Author: markstory

src/Controller/Component/RequestHandlerComponent.php

@@ -355,17 +355,6 @@ public function isWap() {
 		return $this->prefers('wap');
 	}
 
-/**
- * Gets Prototype version if call is Ajax, otherwise empty string.
- * The Prototype library sets a special "Prototype version" HTTP header.
- *
- * @return string|bool When Ajax the prototype version of component making the call otherwise false
- */
-	public function getAjaxVersion() {
-		$httpX = $this->request->env('HTTP_X_PROTOTYPE_VERSION');
-		return ($httpX === null) ? false : $httpX;
-	}
-
 /**
  * Determines which content types the client accepts. Acceptance is based on
  * the file extension parsed by the Router (if present), and by the HTTP_ACCEPT

tests/TestCase/Controller/Component/RequestHandlerComponentTest.php

@@ -604,20 +604,6 @@ public function testRenderAsCalledTwice() {
 		$this->assertEquals('js', $this->Controller->layoutPath);
 	}
 
-/**
- * testRequestClientTypes method
- *
- * @return void
- */
-	public function testRequestClientTypes() {
-		$this->RequestHandler->request->env('HTTP_X_PROTOTYPE_VERSION', '1.5');
-		$this->assertEquals('1.5', $this->RequestHandler->getAjaxVersion());
-
-		$this->RequestHandler->request->env('HTTP_X_REQUESTED_WITH', false);
-		$this->RequestHandler->request->env('HTTP_X_PROTOTYPE_VERSION', false);
-		$this->assertFalse($this->RequestHandler->getAjaxVersion());
-	}
-
 /**
  * testRequestContentTypes method
  *