diff --git a/gfx/thebes/gfxPlatform.cpp b/gfx/thebes/gfxPlatform.cpp
index bc652e609cf..df3aacefa09 100644
--- a/gfx/thebes/gfxPlatform.cpp
+++ b/gfx/thebes/gfxPlatform.cpp
@@ -905,6 +905,9 @@ gfxPlatform::PurgeSkiaCache()
       return;
 
   mSkiaGlue->GetGrContext()->freeGpuResources();
+  // GrContext::flush() doesn't call glFlush. Call it here.
+  mSkiaGlue->GetGLContext()->MakeCurrent();
+  mSkiaGlue->GetGLContext()->fFlush();
 #endif
 }