Make panel adjust bounds per preferred size change notification on Windows.

chrome/browser/ui/browser_window.h

Index: chrome/browser/ui/browser_window.h
===================================================================
--- chrome/browser/ui/browser_window.h	(revision 98900)
+++ chrome/browser/ui/browser_window.h	(working copy)
@@ -33,6 +33,7 @@
 
 namespace gfx {
 class Rect;
+class Size;
 }
 
 class Extension;
@@ -344,6 +345,13 @@
   virtual void ShowKeyboardOverlay(gfx::NativeWindow owning_window) = 0;
 #endif
 
+  // Invoked when the preferred size of the contents in current tab has been
+  // changed. We might choose to update the window size to accomodate this
+  // change.
+  // Note that this won't be fired if we change tabs.
+  virtual void UpdatePreferredSize(TabContents* tab_contents,
+                                   const gfx::Size& pref_size) {}
+
   // Construct a BrowserWindow implementation for the specified |browser|.
   static BrowserWindow* CreateBrowserWindow(Browser* browser);