Libraries: Add missing headers

A C++ source file containing just
    #include <LibFoo/Bar.h>
should always compile cleanly.

This patch adds missing header inclusions that could have caused weird error
messages if they were used in a different context. Also, this confused QtCreator.

Userland/Libraries/LibWeb/DOM/EventDispatcher.h

@@ -27,6 +27,7 @@
 #pragma once
 
 #include <AK/Forward.h>
+#include <LibWeb/DOM/Event.h>
 #include <LibWeb/Forward.h>
 
 namespace Web::DOM {

Userland/Libraries/LibWeb/DOM/Timer.h

@@ -29,6 +29,7 @@
 #include <AK/Forward.h>
 #include <LibCore/Forward.h>
 #include <LibJS/Heap/Handle.h>
+#include <LibJS/Runtime/Function.h>
 #include <LibWeb/Forward.h>
 
 namespace Web::DOM {

Userland/Libraries/LibWeb/FontCache.h

@@ -29,6 +29,7 @@
 #include <AK/FlyString.h>
 #include <AK/HashMap.h>
 #include <AK/String.h>
+#include <LibGfx/Font.h>
 #include <LibGfx/Forward.h>
 
 struct FontSelector {

Userland/Libraries/LibWeb/Layout/SVGPathBox.h

@@ -27,6 +27,7 @@
 #pragma once
 
 #include <LibWeb/Layout/SVGGraphicsBox.h>
+#include <LibWeb/SVG/SVGPathElement.h>
 
 namespace Web::Layout {
 

Userland/Libraries/LibWeb/Page/EditEventHandler.h

@@ -26,6 +26,7 @@
 
 #pragma once
 
+#include <AK/Types.h>
 #include <LibWeb/Forward.h>
 
 namespace Web {

Userland/Libraries/LibWeb/Page/EventHandler.h

@@ -27,6 +27,7 @@
 #pragma once
 
 #include <AK/Forward.h>
+#include <AK/NonnullOwnPtr.h>
 #include <AK/WeakPtr.h>
 #include <Kernel/API/KeyCode.h>
 #include <LibGUI/Forward.h>

Userland/Libraries/LibWeb/Painting/PaintContext.h

@@ -26,6 +26,7 @@
 
 #pragma once
 
+#include <AK/Vector.h>
 #include <LibGfx/Forward.h>
 #include <LibGfx/Palette.h>
 #include <LibGfx/Rect.h>

Userland/Libraries/LibWeb/SVG/SVGContext.h

@@ -26,6 +26,9 @@
 
 #pragma once
 
+#include <AK/Vector.h>
+#include <LibGfx/Color.h>
+
 namespace Web {
 
 class SVGContext {

Userland/Libraries/LibWeb/StylePropertiesModel.h

@@ -28,6 +28,7 @@
 
 #include <AK/NonnullRefPtrVector.h>
 #include <LibGUI/Model.h>
+#include <LibWeb/CSS/StyleProperties.h>
 
 namespace Web {