Move DisplayCutoutController tracking to AwViewMethodsImpl.

This change calls DisplayCutoutController#onAttachedToWindow when either
the WebView is attached to the window, or the FullScreenView is attached
to the window (whichever the AwContents is displaying to).

This is a change in behaviour, but should be more correct. There likely
wasn't an issue beforehand because when switching to full screen,
DisplayCutoutController#setCurrentContainerView was called, which also
requested full screen insets.

Bug: 380261043
Change-Id: I23a607b6450bb53cd37644e5a62ab708c97dfe90
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6513140
Reviewed-by: Peter Pakkenberg <pbirk@chromium.org>
Commit-Queue: Peter Conn <peconn@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1456964}

android_webview/java/src/org/chromium/android_webview/AwContents.java

@@ -3351,8 +3351,6 @@ public class AwContents implements SmartClipProvider {
         // instead attached to a FullScreenView.
         mAwViewMethods.onAttachedToWindow();
 
-        if (mDisplayCutoutController != null) mDisplayCutoutController.onAttachedToWindow();
-
         mAwFrameMetricsListener =
                 AwFrameMetricsListener.maybeCreate(
                         mContainerView, mWindowAndroid.getWindowAndroid());
@@ -4650,6 +4648,8 @@ public class AwContents implements SmartClipProvider {
                 StylusWritingSettingsState.getInstance().registerObserver(mStylusWritingController);
             }
 
+            if (mDisplayCutoutController != null) mDisplayCutoutController.onAttachedToWindow();
+
             mAwWindowCoverageTracker =
                     AwWindowCoverageTracker.getOrCreateForRootView(
                             AwContents.this, mContainerView.getRootView());