ScrollStateCallback: fix clash between enum class NativeScrollBehavior and getter

Rename NativeScrollBehavior getter to GetNativeScrollBehavior to avoid GCC
compilation error:

../../third_party/blink/renderer/core/page/scrolling/scroll_state_callback.h:31:3: error: declaration of ‘blink::NativeScrollBehavior blink::ScrollStateCallback::NativeScrollBehavior() const’ [-fpermissive]
   }
   ^
../../third_party/blink/renderer/core/page/scrolling/scroll_state_callback.h:15:12: error: changes meaning of ‘NativeScrollBehavior’ from ‘enum class blink::NativeScrollBehavior’ [-fpermissive]

Bug: 819294
Change-Id: Idb0fa5649c78171dce179a075222847053268324
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1900998Reviewed-by: David Bokan <bokan@chromium.org>
Commit-Queue: José Dapena Paz <jose.dapena@lge.com>
Cr-Commit-Position: refs/heads/master@{#713116}

third_party/blink/renderer/core/dom/node.cc

@@ -617,13 +617,13 @@ void Node::CallDistributeScroll(ScrollState& scroll_state) {
     NativeDistributeScroll(scroll_state);
     return;
   }
-  if (callback->NativeScrollBehavior() !=
+  if (callback->GetNativeScrollBehavior() !=
       NativeScrollBehavior::kPerformAfterNativeScroll)
     callback->Invoke(&scroll_state);
-  if (callback->NativeScrollBehavior() !=
+  if (callback->GetNativeScrollBehavior() !=
       NativeScrollBehavior::kDisableNativeScroll)
     NativeDistributeScroll(scroll_state);
-  if (callback->NativeScrollBehavior() ==
+  if (callback->GetNativeScrollBehavior() ==
       NativeScrollBehavior::kPerformAfterNativeScroll)
     callback->Invoke(&scroll_state);
 }
@@ -663,13 +663,13 @@ void Node::CallApplyScroll(ScrollState& scroll_state) {
     NativeApplyScroll(scroll_state);
     return;
   }
-  if (callback->NativeScrollBehavior() !=
+  if (callback->GetNativeScrollBehavior() !=
       NativeScrollBehavior::kPerformAfterNativeScroll)
     callback->Invoke(&scroll_state);
-  if (callback->NativeScrollBehavior() !=
+  if (callback->GetNativeScrollBehavior() !=
       NativeScrollBehavior::kDisableNativeScroll)
     NativeApplyScroll(scroll_state);
-  if (callback->NativeScrollBehavior() ==
+  if (callback->GetNativeScrollBehavior() ==
       NativeScrollBehavior::kPerformAfterNativeScroll)
     callback->Invoke(&scroll_state);
 }

third_party/blink/renderer/core/page/scrolling/scroll_state_callback.h

@@ -26,7 +26,7 @@ class ScrollStateCallback : public GarbageCollected<ScrollStateCallback> {
 
   virtual void Invoke(ScrollState*) = 0;
 
-  NativeScrollBehavior NativeScrollBehavior() const {
+  NativeScrollBehavior GetNativeScrollBehavior() const {
     return native_scroll_behavior_;
   }