Merge r231132 - [GTK] WebProcess from WebKitGtk+ 2.19.92 SIGSEVs in W…

…ebCore::TextureMapperGL::~TextureMapperGL

https://bugs.webkit.org/show_bug.cgi?id=184040

Reviewed by Michael Catanzaro.

This can happen when using single shared process model or when the process limit is reached in multiple process
model. In this case, all pages in the same web process with accelerated compositing enabled share the same
compositing thread. Every page sets its GL context as current when rendering a frame, but not when invalidating
the threaded compositor when the page is closed. So, if a hidden tab is closed, the threaded compositor is
invalidated and the GL resources of the current context (the visible page) are destroyed. This is also causing
the blank pages issue when closing a tab related to another one, the current one stops rendering anything because
its GL context has been released. We should make the threaded compositor context current when invalidating it.

* Shared/CoordinatedGraphics/threadedcompositor/ThreadedCompositor.cpp:
(WebKit::ThreadedCompositor::invalidate):

Source/WebKit/ChangeLog

@@ -1,3 +1,21 @@
+2018-04-28  Carlos Garcia Campos  <cgarcia@igalia.com>
+
+        [GTK] WebProcess from WebKitGtk+ 2.19.92 SIGSEVs in WebCore::TextureMapperGL::~TextureMapperGL
+        https://bugs.webkit.org/show_bug.cgi?id=184040
+
+        Reviewed by Michael Catanzaro.
+
+        This can happen when using single shared process model or when the process limit is reached in multiple process
+        model. In this case, all pages in the same web process with accelerated compositing enabled share the same
+        compositing thread. Every page sets its GL context as current when rendering a frame, but not when invalidating
+        the threaded compositor when the page is closed. So, if a hidden tab is closed, the threaded compositor is
+        invalidated and the GL resources of the current context (the visible page) are destroyed. This is also causing
+        the blank pages issue when closing a tab related to another one, the current one stops rendering anything because
+        its GL context has been released. We should make the threaded compositor context current when invalidating it.
+
+        * Shared/CoordinatedGraphics/threadedcompositor/ThreadedCompositor.cpp:
+        (WebKit::ThreadedCompositor::invalidate):
+
 2018-04-24  Zan Dobersek  <zdobersek@igalia.com>
 
         REGRESSION(r230950): Faulty commit sequencing in CoordinatedGraphicsScene

Source/WebKit/Shared/CoordinatedGraphics/threadedcompositor/ThreadedCompositor.cpp

@@ -107,6 +107,8 @@ void ThreadedCompositor::invalidate()
     m_displayRefreshMonitor->invalidate();
 #endif
     m_compositingRunLoop->performTaskSync([this, protectedThis = makeRef(*this)] {
+        if (!m_context || !m_context->makeContextCurrent())
+            return;
         m_scene->purgeGLResources();
         m_context = nullptr;
         m_client.didDestroyGLContext();