Apply override scale from entry points on client

This provides a sandbox-like scaled environment on client side.

- This prevents the metrics and config from being scaled multiple
  times because the entry points are only called from server side,
  there won't have reentrancy for applying the scale.
- App's configuration callback method can get scaled config.
- If override scale is enabled, the legacy compat mode will be
  skipped. That avoids mixing different approaches of scaling.
  - Legacy compat mode is to simulate a 320dp x 480dp screen
    size with density 160 (the surface scale and config scale
    are different).
  - Override scale is to downscale the app for better performance
    (the surface scale and config scale are the same).

Bug: 238416387
Bug: 240335717
Test: atest ActivityThreadTest#testOverrideScale
Test: atest CtsWindowManagerDeviceTestCases:CompatScaleTests
Test: am compat enable DOWNSCALED $pkg
      am compat enable DOWNSCALE_50 $pkg
Change-Id: I0ddf333996f229063511273f8aeb3867c9ba8bda

core/java/android/view/DisplayInfo.java

@@ -723,9 +723,9 @@ public final class DisplayInfo implements Parcelable {
         outMetrics.noncompatWidthPixels  = outMetrics.widthPixels = width;
         outMetrics.noncompatHeightPixels = outMetrics.heightPixels = height;
 
-        if (!compatInfo.equals(CompatibilityInfo.DEFAULT_COMPATIBILITY_INFO)) {
-            compatInfo.applyToDisplayMetrics(outMetrics);
-        }
+        // Apply to size if the configuration is EMPTY because the size is from real display info.
+        final boolean applyToSize = configuration != null && appBounds == null;
+        compatInfo.applyDisplayMetricsIfNeeded(outMetrics, applyToSize);
     }
 
     // For debugging purposes

core/java/android/view/ViewRootImpl.java

@@ -1787,6 +1787,7 @@ public final class ViewRootImpl implements ViewParent,
 
         final ClientWindowFrames frames = (ClientWindowFrames) args.arg1;
         final MergedConfiguration mergedConfiguration = (MergedConfiguration) args.arg2;
+        CompatibilityInfo.applyOverrideScaleIfNeeded(mergedConfiguration);
         final boolean forceNextWindowRelayout = args.argi1 != 0;
         final int displayId = args.argi3;
         final int resizeMode = args.argi5;
@@ -8242,6 +8243,7 @@ public final class ViewRootImpl implements ViewParent,
                 mTranslator.translateSourceControlsInScreenToAppWindow(mTempControls);
             }
             mInvSizeCompatScale = 1f / mTmpFrames.sizeCompatScale;
+            CompatibilityInfo.applyOverrideScaleIfNeeded(mPendingMergedConfiguration);
             mInsetsController.onStateChanged(mTempInsets);
             mInsetsController.onControlsChanged(mTempControls);