Fix sizing issues in the tab modal signin flow.

chrome/browser/ui/signin_view_controller_delegate.h

Index: chrome/browser/ui/signin_view_controller_delegate.h
diff --git a/chrome/browser/ui/signin_view_controller_delegate.h b/chrome/browser/ui/signin_view_controller_delegate.h
index 85ada3281fd8ccb07e4bd70637a66a20a8e5f11e..a504d1340df8d0d2c0aa2280fdc87418d961a252 100644
--- a/chrome/browser/ui/signin_view_controller_delegate.h
+++ b/chrome/browser/ui/signin_view_controller_delegate.h
@@ -36,6 +36,15 @@ class SigninViewControllerDelegate : public content::WebContentsDelegate {
 
   void CloseModalSignin();
 
+  // Either navigates back in the signin flow if the history state allows it or
+  // closes the flow otherwise.
+  void PerformNavigation();
+
+  // This will be called by the base class to request a resize of the native
+  // view hosting the content to |height|. |height| is the total height of the
+  // content, in pixels.
+  virtual void ResizeNativeView(int height) = 0;
+
  protected:
   SigninViewControllerDelegate(SigninViewController* signin_view_controller,
                                content::WebContents* web_contents);
@@ -48,10 +57,6 @@ class SigninViewControllerDelegate : public content::WebContentsDelegate {
   void LoadingStateChanged(content::WebContents* source,
                            bool to_different_document) override;
 
-  // Handles the web ui message sent when the navigation button is clicked by
-  // the user, requesting either a back navigation or closing the dialog.
-  void HandleNavigationButtonClicked(const base::ListValue* args);
-
   // This will be called by this base class when the tab-modal window must be
   // closed. This should close the platform-specific window that is currently
   // showing the sign in flow or the sync confirmation dialog.