Issue Id: b676d149-e6c7-9cfa-a105-dfa445c537eb

Versions
- 0.10.2
Stack
TypeError: Cannot read property 'getLineCount' of null
[/vs/editor/contrib/codelens/browser/codelens.ts#L536:46 (CodeLensContribution.renderCodeLensSymbols)](https://github.com/microsoft/vscode/blob/7cc0c602a2b802b09a3f56b68a1a61ee9e8f0066/src/vs/editor/contrib/codelens/browser/codelens.ts#L536:46 %28CodeLensContribution.renderCodeLensSymbols%29)
[/vs/editor/contrib/codelens/browser/codelens.ts#L451:10 (CodeLensContribution.onModelChange)](https://github.com/microsoft/vscode/blob/7cc0c602a2b802b09a3f56b68a1a61ee9e8f0066/src/vs/editor/contrib/codelens/browser/codelens.ts#L451:10 %28CodeLensContribution.onModelChange%29)
[/vs/base/common/winjs.base.raw.js#L1440:0 (onComplete)](https://github.com/microsoft/vscode/blob/7cc0c602a2b802b09a3f56b68a1a61ee9e8f0066/src/vs/base/common/winjs.base.raw.js#L1440:0 %28onComplete%29)
[/vs/base/common/winjs.base.raw.js#L1127:0 (_notify)](https://github.com/microsoft/vscode/blob/7cc0c602a2b802b09a3f56b68a1a61ee9e8f0066/src/vs/base/common/winjs.base.raw.js#L1127:0 %28_notify%29)
[/vs/base/common/winjs.base.raw.js#L1343:0 (enter)](https://github.com/microsoft/vscode/blob/7cc0c602a2b802b09a3f56b68a1a61ee9e8f0066/src/vs/base/common/winjs.base.raw.js#L1343:0 %28enter%29)
[/vs/base/common/winjs.base.raw.js#L1311:0 (_run)](https://github.com/microsoft/vscode/blob/7cc0c602a2b802b09a3f56b68a1a61ee9e8f0066/src/vs/base/common/winjs.base.raw.js#L1311:0 %28_run%29)
[/vs/base/common/winjs.base.raw.js#L2072:0 (complete)](https://github.com/microsoft/vscode/blob/7cc0c602a2b802b09a3f56b68a1a61ee9e8f0066/src/vs/base/common/winjs.base.raw.js#L2072:0 %28complete%29)
[/vs/base/common/winjs.base.raw.js#L2097:0 (argDone)](https://github.com/microsoft/vscode/blob/7cc0c602a2b802b09a3f56b68a1a61ee9e8f0066/src/vs/base/common/winjs.base.raw.js#L2097:0 %28argDone%29)
[/vs/base/common/winjs.base.raw.js#L1440:0 (onComplete)](https://github.com/microsoft/vscode/blob/7cc0c602a2b802b09a3f56b68a1a61ee9e8f0066/src/vs/base/common/winjs.base.raw.js#L1440:0 %28onComplete%29)
[/vs/base/common/winjs.base.raw.js#L1176:0 (_notify)](https://github.com/microsoft/vscode/blob/7cc0c602a2b802b09a3f56b68a1a61ee9e8f0066/src/vs/base/common/winjs.base.raw.js#L1176:0 %28_notify%29)