Flutter Gallery issues when tapping on 2 demos simultaneously #12470

Steps to Reproduce

1. Start the Flutter Gallery app
2. With 2 fingers tap on 2 demos simultaneously (e.g on Pesto and Shrine)

Repro rate is about 50%, some times you will get the same demo opened twice (e.g you see Shrine, and when you hit back it will pop one page and you're back to Shrine), some times it shows the red exception screen with:

I/flutter ( 8129): ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
I/flutter ( 8129): The following assertion was thrown building ShrinePage(state: ShrinePageState#937bb):
I/flutter ( 8129): Multiple widgets used the same GlobalKey.
I/flutter ( 8129): The key [LabeledGlobalKey#8c7e7 Shrine Home] was used by multiple widgets. The
I/flutter ( 8129): parents of those widgets were:
I/flutter ( 8129): - ShrinePage(state: ShrinePageState#92c4b)
I/flutter ( 8129): - ShrinePage(state: ShrinePageState#937bb)
I/flutter ( 8129): A GlobalKey can only be specified on one widget at a time in the widget tree.
I/flutter ( 8129):
I/flutter ( 8129): When the exception was thrown, this was the stack:
I/flutter ( 8129): #0 GlobalKey._debugReserveFor. (package:flutter/src/widgets/framework.dart:231)
I/flutter ( 8129): #1 GlobalKey._debugReserveFor (package:flutter/src/widgets/framework.dart:249)
I/flutter ( 8129): #2 Element.updateChild. (package:flutter/src/widgets/framework.dart:2659)
I/flutter ( 8129): #3 Element.updateChild (package:flutter/src/widgets/framework.dart:2662)
I/flutter ( 8129): #4 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3557)
I/flutter ( 8129): #5 Element.rebuild (package:flutter/src/widgets/framework.dart:3446)
I/flutter ( 8129): #6 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3525)
I/flutter ( 8129): #7 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:3663)
I/flutter ( 8129): #8 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3520)
I/flutter ( 8129): #9 Element.inflateWidget (package:flutter/src/widgets/framework.dart:2885)
I/flutter ( 8129): #10 Element.updateChild (package:flutter/src/widgets/framework.dart:2688)
I/flutter ( 8129): #11 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3557)
I/flutter ( 8129): #12 Element.rebuild (package:flutter/src/widgets/framework.dart:3446)
I/flutter ( 8129): #13 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3525)
I/flutter ( 8129): #14 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:3663)
I/flutter ( 8129): #15 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3520)
I/flutter ( 8129): #16 Element.inflateWidget (package:flutter/src/widgets/framework.dart:2885)
I/flutter ( 8129): #17 Element.updateChild (package:flutter/src/widgets/framework.dart:2688)
I/flutter ( 8129): #18 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3557)
I/flutter ( 8129): #19 Element.rebuild (package:flutter/src/widgets/framework.dart:3446)
I/flutter ( 8129): #20 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3525)
I/flutter ( 8129): #21 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3520)
I/flutter ( 8129): #22 Element.inflateWidget (package:flutter/src/widgets/framework.dart:2885)
I/flutter ( 8129): #23 Element.updateChild (package:flutter/src/widgets/framework.dart:2688)
I/flutter ( 8129): #24 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3557)
I/flutter ( 8129): #25 Element.rebuild (package:flutter/src/widgets/framework.dart:3446)
I/flutter ( 8129): #26 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3525)
I/flutter ( 8129): #27 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3520)
I/flutter ( 8129): #28 Element.inflateWidget (package:flutter/src/widgets/framework.dart:2885)
I/flutter ( 8129): #29 Element.updateChild (package:flutter/src/widgets/framework.dart:2688)
I/flutter ( 8129): #30 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3557)
I/flutter ( 8129): #31 Element.rebuild (package:flutter/src/widgets/framework.dart:3446)
I/flutter ( 8129): #32 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3525)
I/flutter ( 8129): #33 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3520)
I/flutter ( 8129): #34 Element.inflateWidget (package:flutter/src/widgets/framework.dart:2885)
I/flutter ( 8129): #35 Element.updateChild (package:flutter/src/widgets/framework.dart:2688)
I/flutter ( 8129): #36 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3557)
I/flutter ( 8129): #37 Element.rebuild (package:flutter/src/widgets/framework.dart:3446)
I/flutter ( 8129): #38 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3525)
I/flutter ( 8129): #39 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3520)
I/flutter ( 8129): #40 Element.inflateWidget (package:flutter/src/widgets/framework.dart:2885)
I/flutter ( 8129): #41 Element.updateChild (package:flutter/src/widgets/framework.dart:2688)
I/flutter ( 8129): #42 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3557)
I/flutter ( 8129): #43 Element.rebuild (package:flutter/src/widgets/framework.dart:3446)
I/flutter ( 8129): #44 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3525)
I/flutter ( 8129): #45 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3520)
I/flutter ( 8129): #46 Element.inflateWidget (package:flutter/src/widgets/framework.dart:2885)
I/flutter ( 8129): #47 Element.updateChild (package:flutter/src/widgets/framework.dart:2688)
I/flutter ( 8129): #48 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3557)
I/flutter ( 8129): #49 Element.rebuild (package:flutter/src/widgets/framework.dart:3446)
I/flutter ( 8129): #50 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3525)
I/flutter ( 8129): #51 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3520)
I/flutter ( 8129): #52 Element.inflateWidget (package:flutter/src/widgets/framework.dart:2885)
I/flutter ( 8129): #53 Element.updateChild (package:flutter/src/widgets/framework.dart:2688)
I/flutter ( 8129): #54 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3557)
I/flutter ( 8129): #55 Element.rebuild (package:flutter/src/widgets/framework.dart:3446)
I/flutter ( 8129): #56 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3525)
I/flutter ( 8129): #57 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3520)
I/flutter ( 8129): #58 Element.inflateWidget (package:flutter/src/widgets/framework.dart:2885)
I/flutter ( 8129): #59 Element.updateChild (package:flutter/src/widgets/framework.dart:2688)
I/flutter ( 8129): #60 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:4528)
I/flutter ( 8129): #61 Element.inflateWidget (package:flutter/src/widgets/framework.dart:2885)
I/flutter ( 8129): #62 Element.updateChild (package:flutter/src/widgets/framework.dart:2688)
I/flutter ( 8129): #63 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:4528)
I/flutter ( 8129): #64 Element.inflateWidget (package:flutter/src/widgets/framework.dart:2885)
I/flutter ( 8129): #65 Element.updateChild (package:flutter/src/widgets/framework.dart:2688)
I/flutter ( 8129): #66 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3557)
I/flutter ( 8129): #67 Element.rebuild (package:flutter/src/widgets/framework.dart:3446)
I/flutter ( 8129): #68 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3525)
I/flutter ( 8129): #69 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:3663)
I/flutter ( 8129): #70 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3520)
I/flutter ( 8129): #71 Element.inflateWidget (package:flutter/src/widgets/framework.dart:2885)
I/flutter ( 8129): #72 Element.updateChild (package:flutter/src/widgets/framework.dart:2688)
I/flutter ( 8129): #73 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3557)
I/flutter ( 8129): #74 Element.rebuild (package:flutter/src/widgets/framework.dart:3446)
I/flutter ( 8129): #75 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3525)
I/flutter ( 8129): #76 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3520)
I/flutter ( 8129): #77 Element.inflateWidget (package:flutter/src/widgets/framework.dart:2885)
I/flutter ( 8129): #78 Element.updateChild (package:flutter/src/widgets/framework.dart:2688)
I/flutter ( 8129): #79 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:4528)
I/flutter ( 8129): #80 Element.inflateWidget (package:flutter/src/widgets/framework.dart:2885)
I/flutter ( 8129): #81 Element.updateChild (package:flutter/src/widgets/framework.dart:2688)
I/flutter ( 8129): #82 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:4528)
I/flutter ( 8129): #83 Element.inflateWidget (package:flutter/src/widgets/framework.dart:2885)
I/flutter ( 8129): #84 Element.updateChild (package:flutter/src/widgets/framework.dart:2688)
I/flutter ( 8129): #85 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3557)
I/flutter ( 8129): #86 Element.rebuild (package:flutter/src/widgets/framework.dart:3446)
I/flutter ( 8129): #87 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3525)
I/flutter ( 8129): #88 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3520)
I/flutter ( 8129): #89 Element.inflateWidget (package:flutter/src/widgets/framework.dart:2885)
I/flutter ( 8129): #90 Element.updateChild (package:flutter/src/widgets/framework.dart:2688)
I/flutter ( 8129): #91 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:4528)
I/flutter ( 8129): #92 Element.inflateWidget (package:flutter/src/widgets/framework.dart:2885)
I/flutter ( 8129): #93 Element.updateChild (package:flutter/src/widgets/framework.dart:2688)
I/flutter ( 8129): #94 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3557)
I/flutter ( 8129): #95 Element.rebuild (package:flutter/src/widgets/framework.dart:3446)
I/flutter ( 8129): #96 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3525)
I/flutter ( 8129): #97 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:3663)
I/flutter ( 8129): #98 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3520)
I/flutter ( 8129): #99 Element.inflateWidget (package:flutter/src/widgets/framework.dart:2885)
I/flutter ( 8129): #100 Element.updateChild (package:flutter/src/widgets/framework.dart:2688)
I/flutter ( 8129): #101 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3557)
I/flutter ( 8129): #102 Element.rebuild (package:flutter/src/widgets/framework.dart:3446)
I/flutter ( 8129): #103 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3525)
I/flutter ( 8129): #104 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:3663)
I/flutter ( 8129): #105 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3520)
I/flutter ( 8129): #106 Element.inflateWidget (package:flutter/src/widgets/framework.dart:2885)
I/flutter ( 8129): #107 Element.updateChild (package:flutter/src/widgets/framework.dart:2688)
I/flutter ( 8129): #108 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3557)
I/flutter ( 8129): #109 Element.rebuild (package:flutter/src/widgets/framework.dart:3446)
I/flutter ( 8129): #110 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:3525)
I/flutter ( 8129): #111 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:3663)
I/flutter ( 8129): #112 ComponentElement.mount (package:flutter/src/widgets/framework.dart:3520)
I/flutter ( 8129): #113 Element.inflateWidget (package:flutter/src/widgets/framework.dart:2885)
I/flutter ( 8129): #114 Element.updateChild (package:flutter/src/widgets/framework.dart:2688)
I/flutter ( 8129): #115 RenderObjectElement.updateChildren (package:flutter/src/widgets/framework.dart:4320)
I/flutter ( 8129): #116 MultiChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4643)
I/flutter ( 8129): #117 Element.updateChild (package:flutter/src/widgets/framework.dart:2677)
I/flutter ( 8129): #118 _TheatreElement.update (package:flutter/src/widgets/overlay.dart:507)
I/flutter ( 8129): #119 Element.updateChild (package:flutter/src/widgets/framework.dart:2677)
I/flutter ( 8129): #120 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3557)
I/flutter ( 8129): #121 Element.rebuild (package:flutter/src/widgets/framework.dart:3446)
I/flutter ( 8129): #122 StatefulElement.update (package:flutter/src/widgets/framework.dart:3682)
I/flutter ( 8129): #123 Element.updateChild (package:flutter/src/widgets/framework.dart:2677)
I/flutter ( 8129): #124 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3557)
I/flutter ( 8129): #125 Element.rebuild (package:flutter/src/widgets/framework.dart:3446)
I/flutter ( 8129): #126 ProxyElement.update (package:flutter/src/widgets/framework.dart:3792)
I/flutter ( 8129): #127 Element.updateChild (package:flutter/src/widgets/framework.dart:2677)
I/flutter ( 8129): #128 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4535)
I/flutter ( 8129): #129 Element.updateChild (package:flutter/src/widgets/framework.dart:2677)
I/flutter ( 8129): #130 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3557)
I/flutter ( 8129): #131 Element.rebuild (package:flutter/src/widgets/framework.dart:3446)
I/flutter ( 8129): #132 StatefulElement.update (package:flutter/src/widgets/framework.dart:3682)
I/flutter ( 8129): #133 Element.updateChild (package:flutter/src/widgets/framework.dart:2677)
I/flutter ( 8129): #134 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4535)
I/flutter ( 8129): #135 Element.updateChild (package:flutter/src/widgets/framework.dart:2677)
I/flutter ( 8129): #136 SingleChildRenderObjectElement.update (package:flutter/src/widgets/framework.dart:4535)
I/flutter ( 8129): #137 Element.updateChild (package:flutter/src/widgets/framework.dart:2677)
I/flutter ( 8129): #138 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:3557)
I/flutter ( 8129): #139 Element.rebuild (package:flutter/src/widgets/framework.dart:3446)
I/flutter ( 8129): #140 BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2246)
I/flutter ( 8129): #141 BindingBase&SchedulerBinding&GestureBinding&ServicesBinding&RendererBinding&WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:580)
I/flutter ( 8129): #142 BindingBase&SchedulerBinding&GestureBinding&ServicesBinding&RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:200)
I/flutter ( 8129): #143 BindingBase&SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:713)
I/flutter ( 8129): #144 BindingBase&SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:649)
I/flutter ( 8129): #145 _invoke (file:///b/build/slave/Linux_Engine/build/src/flutter/lib/ui/hooks.dart:91)
I/flutter ( 8129): #146 _drawFrame (file:///b/build/slave/Linux_Engine/build/src/flutter/lib/ui/hooks.dart:80)
I/flutter ( 8129): ════════════════════════════════════════════════════════════════════════════════════════════════════
I/flutter ( 8129): Another exception was thrown: Multiple widgets used the same GlobalKey.