Prevent DecorContext from creating DisplayContext for default display.

The previous implementation of createDisplayContext() was essentially a
noop within ResourcesManager when the default display was passed. However,
the current implementation always overrides the configuration with the provided
display's metrics so when a DecorContext with the default display is
created a new ResourcesImpl object is also created due to the difference in
configuration. This CL changes the DecorContext logic to match the
previous implemenation where the configuration is only overriden for a
non-default display thus only creating a new ResourcesImpl object for
non-default displays.

Bug: 166174272
Test: atest google/perf/app-startup/benchmark-app-hermetic/cold-dropcache-test -v
Test: atest com.android.internal.policy.DecorContextTest

Change-Id: I05920c4f7987ffcaec8b197e8636606c04b418d4

1 files changed, 13 insertions, 3 deletions

diff --git a/core/java/com/android/internal/policy/DecorContext.java b/core/java/com/android/internal/policy/DecorContext.java
index 51b41198e272..5e34c15c42e2 100644
--- a/core/java/com/android/internal/policy/DecorContext.java
+++ b/core/java/com/android/internal/policy/DecorContext.java
@@ -20,8 +20,10 @@ import android.content.AutofillOptions;
 import android.content.ContentCaptureOptions;
 import android.content.Context;
 import android.content.res.AssetManager;
+import android.content.res.Configuration;
 import android.content.res.Resources;
 import android.view.ContextThemeWrapper;
+import android.view.Display;
 import android.view.contentcapture.ContentCaptureManager;
 
 import com.android.internal.annotations.VisibleForTesting;
@@ -47,9 +49,17 @@ public class DecorContext extends ContextThemeWrapper {
     public DecorContext(Context baseContext, PhoneWindow phoneWindow) {
         super(null /* base */, null);
         setPhoneWindow(phoneWindow);
-        final Context displayContext = baseContext.createDisplayContext(
-                // TODO(b/149790106): Non-activity context can be passed.
-                phoneWindow.getContext().getDisplayNoVerify());
+        // TODO(b/149790106): Non-activity context can be passed.
+        final Display display = phoneWindow.getContext().getDisplayNoVerify();
+        final Context displayContext;
+        if (display.getDisplayId() == Display.DEFAULT_DISPLAY) {
+            // TODO(b/166174272): Creating a display context for the default display will result
+            // in additional resource creation.
+            displayContext = baseContext.createConfigurationContext(Configuration.EMPTY);
+            displayContext.updateDisplay(Display.DEFAULT_DISPLAY);
+        } else {
+            displayContext = baseContext.createDisplayContext(display);
+        }
         attachBaseContext(displayContext);
     }