Need to check the context wasn't lost in WebGL2RenderingContext::read…

…Buffer()

https://bugs.webkit.org/show_bug.cgi?id=241477
<rdar://94289317>

Patch by Antoine Quint <graouts@apple.com> on 2022-06-09
Reviewed by Dean Jackson.

All other APIs exposed on WebGL2RenderingContext are guarded by isContextLostOrPending()
checks, and readBuffer() should be no exception.

* Source/WebCore/html/canvas/WebGL2RenderingContext.cpp:
(WebCore::WebGL2RenderingContext::readBuffer):

Canonical link: https://commits.webkit.org/251436@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@295430 268f45cc-cd09-0410-ab3c-d52691b4dbfc

Source/WebCore/html/canvas/WebGL2RenderingContext.cpp

@@ -811,6 +811,9 @@ void WebGL2RenderingContext::invalidateSubFramebuffer(GCGLenum target, const Vec
 
 void WebGL2RenderingContext::readBuffer(GCGLenum src)
 {
+    if (isContextLostOrPending())
+        return;
+
     if (src == GraphicsContextGL::BACK) {
         // Because the backbuffer is simulated on all current WebKit ports, we need to change BACK to COLOR_ATTACHMENT0.
         if (m_readFramebufferBinding) {