Allow the EntityContext to read from the request data.

Reading from the request data is helpful when you are making forms, as
you might need to access data that has not been added to the entities
that compose the context.

src/View/Form/EntityContext.php

@@ -194,6 +194,10 @@ public function isCreate() {
  * @return mixed The value of the field or null on a miss.
  */
 	public function val($field) {
+		$val = $this->_request->data($field);
+		if ($val !== null) {
+			return $val;
+		}
 		if (empty($this->_context['entity'])) {
 			return null;
 		}

tests/TestCase/View/Form/EntityContextTest.php

@@ -377,6 +377,29 @@ public function testValBasic() {
 		$this->assertNull($result);
 	}
 
+/**
+ * Test that val() reads from the request.
+ *
+ * @return void
+ */
+	public function testValReadsRequest() {
+		$this->request->data = [
+			'title' => 'New title',
+			'notInEntity' => 'yes',
+		];
+		$row = new Entity([
+			'title' => 'Test entity',
+			'body' => 'Something new'
+		]);
+		$context = new EntityContext($this->request, [
+			'entity' => $row,
+			'table' => 'Articles',
+		]);
+		$this->assertEquals('New title', $context->val('title'));
+		$this->assertEquals('yes', $context->val('notInEntity'));
+		$this->assertEquals($row->body, $context->val('body'));
+	}
+
 /**
  * Test reading values from associated entities.
  *