Fix the problem that the minimized docked panel is not unsqueezed back to its...

Fix the problem that the minimized docked panel is not unsqueezed back to its original size when the restore button is clicked

The fix is to make Panel::OnRestoreButtonClicked call Panel::OnTitlebarClicked such that the logic provided in OnTitlebarClicked can take effect

BUG=244781
TEST=Manual test by following repro steps as in the bug

Review URL: https://chromiumcodereview.appspot.com/15807006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@203022 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/ui/panels/panel.cc

@@ -470,8 +470,8 @@ void Panel::OnMinimizeButtonClicked(panel::ClickModifier modifier) {
 }
 
 void Panel::OnRestoreButtonClicked(panel::ClickModifier modifier) {
-  if (collection_)
-    collection_->OnRestoreButtonClicked(this, modifier);
+  // Clicking the restore button has the same behavior as clicking the titlebar.
+  OnTitlebarClicked(modifier);
 }
 
 void Panel::OnWindowSizeAvailable() {