Make Autofill work again on iPads running iOS 9.

ios/chrome/browser/autofill/form_input_accessory_view_controller.h

Index: ios/chrome/browser/autofill/form_input_accessory_view_controller.h
diff --git a/ios/chrome/browser/autofill/form_input_accessory_view_controller.h b/ios/chrome/browser/autofill/form_input_accessory_view_controller.h
index 0ed51250837151ae240c44ac9c9c24a5deb7fa2f..03a474e0a5f314389ce3b8101c9db6339dd1de8a 100644
--- a/ios/chrome/browser/autofill/form_input_accessory_view_controller.h
+++ b/ios/chrome/browser/autofill/form_input_accessory_view_controller.h
@@ -16,6 +16,7 @@ namespace autofill {
 extern NSString* const kFormSuggestionAssistButtonPreviousElement;
 extern NSString* const kFormSuggestionAssistButtonNextElement;
 extern NSString* const kFormSuggestionAssistButtonDone;
+extern CGFloat const kInputAccessoryHeight;
 }  // namespace autofill
 
 @protocol FormInputAccessoryViewProvider;
@@ -80,6 +81,12 @@ typedef void (^AccessoryViewReadyCompletion)(
 - (instancetype)initWithWebState:(web::WebState*)webState
                        providers:(NSArray*)providers;
 
+// Notifies the controller that the owning tab was shown.
+- (void)wasShown;
+
+// Notifies the controller that the owning tab was hidden.
+- (void)wasHidden;
+
 // Hides the default input accessory view and replaces it with one that shows
 // |customView| and form navigation controls.
 - (void)showCustomInputAccessoryView:(UIView*)customView;