Fixes bug where match preview wouldn't get hidden if match preview was

chrome/browser/tab_contents/match_preview.cc

Index: chrome/browser/tab_contents/match_preview.cc
diff --git a/chrome/browser/tab_contents/match_preview.cc b/chrome/browser/tab_contents/match_preview.cc
index 1d24287b2cb26412597dff9bdc6adedbbb178b83..1ddd4e9bf5def4b0d15437293358e06a6bfaa10e 100644
--- a/chrome/browser/tab_contents/match_preview.cc
+++ b/chrome/browser/tab_contents/match_preview.cc
@@ -505,6 +505,11 @@ void MatchPreview::SetOmniboxBounds(const gfx::Rect& bounds) {
 }
 
 void MatchPreview::DestroyPreviewContents() {
+  if (!preview_contents_.get()) {
+    // We're not showing anything, nothing to do.
+    return;
+  }
+
   delegate_->HideMatchPreview();
   delete ReleasePreviewContents(false);
 }