Hook up SetInstantPreviewHeight for ChromeOS.

chrome/test/base/test_browser_window.h

Index: chrome/test/base/test_browser_window.h
diff --git a/chrome/test/base/test_browser_window.h b/chrome/test/base/test_browser_window.h
index 895c1d10715d0de8a17ae31f3235e3633fb7eaae..ff48f379f94cc9324c327f5491eee7cc491f9ce6 100644
--- a/chrome/test/base/test_browser_window.h
+++ b/chrome/test/base/test_browser_window.h
@@ -129,7 +129,9 @@ class TestBrowserWindow : public BrowserWindow {
   virtual bool InPresentationMode() OVERRIDE;
 #endif
 
-  virtual void ShowInstant(TabContents* preview_contents) OVERRIDE {}
+  virtual void ShowInstant(TabContents* preview_contents,
+                           int height,
+                           InstantSizeUnits units) OVERRIDE {}
   virtual void HideInstant() OVERRIDE {}
   virtual gfx::Rect GetInstantBounds() OVERRIDE;
   virtual bool IsInstantTabShowing() OVERRIDE;