[Chromecast] Fix assert failure + add test in SwapWithBounds path

cc/test/test_web_graphics_context_3d.h

Index: cc/test/test_web_graphics_context_3d.h
diff --git a/cc/test/test_web_graphics_context_3d.h b/cc/test/test_web_graphics_context_3d.h
index 233c067e65648b1b31c2ff1f0b5c177b57dc53d5..617d09fff2931dfe477d095cfbf67188180eff54 100644
--- a/cc/test/test_web_graphics_context_3d.h
+++ b/cc/test/test_web_graphics_context_3d.h
@@ -314,6 +314,9 @@ class TestWebGraphicsContext3D {
   void set_have_post_sub_buffer(bool have) {
     test_capabilities_.post_sub_buffer = have;
   }
+  void set_have_swap_buffers_with_bounds(bool have) {
+    test_capabilities_.swap_buffers_with_bounds = have;
+  }
   void set_have_commit_overlay_planes(bool have) {
     test_capabilities_.commit_overlay_planes = have;
   }