Use const ref for LocalFrame::LocalFrameRoot and FrameTree::Top

third_party/WebKit/Source/core/input/GestureManager.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/input/GestureManager.h"
 
 #include "core/dom/Document.h"
 #include "core/dom/DocumentUserGestureToken.h"
 #include "core/editing/SelectionController.h"
 #include "core/events/GestureEvent.h"
@@ skipping 157 matching lines @@
   // Do a new hit-test in case the mousemove event changed the DOM.
   // Note that if the original hit test wasn't over an element (eg. was over a
   // scrollbar) we don't want to re-hit-test because it may be in the wrong
   // frame (and there's no way the page could have seen the event anyway).  Also
   // note that the position of the frame may have changed, so we need to
   // recompute the content co-ordinates (updating layout/style as
   // hitTestResultAtPoint normally would).
   // FIXME: Use a hit-test cache to avoid unnecessary hit tests.
   // http://crbug.com/398920
   if (current_hit_test.InnerNode()) {
-    LocalFrame* main_frame = frame_->LocalFrameRoot();
-    if (main_frame && main_frame->View())
-      main_frame->View()->UpdateLifecycleToCompositingCleanPlusScrolling();
+    LocalFrame& main_frame = frame_->LocalFrameRoot();
+    if (main_frame.View())
+      main_frame.View()->UpdateLifecycleToCompositingCleanPlusScrolling();
     adjusted_point = frame_view->RootFrameToContents(
         FlooredIntPoint(gesture_event.PositionInRootFrame()));
     current_hit_test = EventHandlingUtil::HitTestResultInFrame(
         frame_, adjusted_point, hit_type);
   }
 
   // Capture data for showUnhandledTapUIIfNeeded.
   IntPoint tapped_position =
       FlooredIntPoint(gesture_event.PositionInRootFrame());
   Node* tapped_node = current_hit_test.InnerNode();
@@ skipping 39 matching lines @@
   if (current_hit_test.InnerNode()) {
     DCHECK(gesture_event.GetType() == WebInputEvent::kGestureTap);
     HitTestResult result = current_hit_test;
     result.SetToShadowHostIfInRestrictedShadowRoot();
     frame_->GetChromeClient().OnMouseDown(*result.InnerNode());
   }
 
   // FIXME: Use a hit-test cache to avoid unnecessary hit tests.
   // http://crbug.com/398920
   if (current_hit_test.InnerNode()) {
-    LocalFrame* main_frame = frame_->LocalFrameRoot();
-    if (main_frame && main_frame->View())
-      main_frame->View()->UpdateAllLifecyclePhases();
+    LocalFrame& main_frame = frame_->LocalFrameRoot();
+    if (main_frame.View())
+      main_frame.View()->UpdateAllLifecyclePhases();
     adjusted_point = frame_view->RootFrameToContents(tapped_position);
     current_hit_test = EventHandlingUtil::HitTestResultInFrame(
         frame_, adjusted_point, hit_type);
   }
 
   WebMouseEvent fake_mouse_up(
       WebInputEvent::kMouseUp, gesture_event,
       WebPointerProperties::Button::kLeft, gesture_event.TapCount(),
       static_cast<WebInputEvent::Modifiers>(
           modifiers | WebInputEvent::Modifiers::kIsCompatibilityEventForTouch),
@@ skipping 175 matching lines @@
   }
   return WebInputEventResult::kNotHandled;
 }
 
 WTF::Optional<WTF::TimeTicks> GestureManager::GetLastShowPressTimestamp()
     const {
   return last_show_press_timestamp_;
 }
 
 }  // namespace blink