Backport to R19 of r132638 r133017 r133579 r133732

content/browser/renderer_host/image_transport_factory.cc

Index: content/browser/renderer_host/image_transport_factory.cc
diff --git a/content/browser/renderer_host/image_transport_factory.cc b/content/browser/renderer_host/image_transport_factory.cc
index 3b7d630543b9cb400341ab7d41ee743df1f52d45..0248dede7acf3a8e7283cc5f6f8af711380a17f2 100644
--- a/content/browser/renderer_host/image_transport_factory.cc
+++ b/content/browser/renderer_host/image_transport_factory.cc
@@ -307,6 +307,7 @@ class GpuProcessTransportFactory : public ui::ContextFactory,
           surface.parent_context_id == context_id) {
         data->shared_context->deleteTexture(surface.parent_texture_id[0]);
         data->shared_context->deleteTexture(surface.parent_texture_id[1]);
+        data->shared_context->flush();
         break;
       }
     }