Fix shelf crash on windows
Fix shelf crash on windows

In debug builds it doesn't appear that windows makes string constants
equal if the text is the same. This means the getter always returned null.

BUG=none
TEST=none
R=msw@chromium.org

Review URL: https://codereview.chromium.org/1736293004

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#378058}

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