Switch all contexts in a share group to be on the same screen as the window they present to.

ui/gl/gl_share_group.h

Index: ui/gl/gl_share_group.h
diff --git a/ui/gl/gl_share_group.h b/ui/gl/gl_share_group.h
index e069d657e62f3d40a7573878ff8fafa151151c88..1deed63c541c1584becd2fa0fc954f6392a5d8e9 100644
--- a/ui/gl/gl_share_group.h
+++ b/ui/gl/gl_share_group.h
@@ -38,6 +38,13 @@ class GL_EXPORT GLShareGroup : public base::RefCounted<GLShareGroup> {
   void SetSharedContext(GLContext* context);
   GLContext* GetSharedContext();
 
+#if defined(OS_MACOSX)
+  // Sets and returns the ID of the renderer that all contexts in this share
+  // group should be on.
+  void SetRendererID(int renderer_id);
+  int GetRendererID();
+#endif
+
  private:
   friend class base::RefCounted<GLShareGroup>;
 
@@ -50,6 +57,10 @@ class GL_EXPORT GLShareGroup : public base::RefCounted<GLShareGroup> {
 
   GLContext* shared_context_;
 
+#if defined(OS_MACOSX)
+  int renderer_id_;
+#endif
+
   DISALLOW_COPY_AND_ASSIGN(GLShareGroup);
 };