Fix Dimensions not updating on Android (#31973)

Summary:
When retrieving the device dimensions through the JS `Dimensions` utility, the result of `Dimensions.get` can be incorrect on Android.

### Related issues

- https://github.com/facebook/react-native/issues/29105
- https://github.com/facebook/react-native/issues/29451
- https://github.com/facebook/react-native/issues/29323

The issue is caused by the Android `DeviceInfoModule` that provides initial screen dimensions and then subsequently updates those by emitting `didUpdateDimensions` events. The assumption in that implementation is that the initial display metrics will not have changed prior to the first check for updated metrics. However that is not the case as the device may be rotated (as shown in the attached video).

The solution in this PR is to keep track of the initial dimensions for comparison at the first check for updated metrics.

## Changelog

[Android] [Fixed] - Fix Dimensions not updating

Pull Request resolved: https://github.com/facebook/react-native/pull/31973

Test Plan:
### Steps to reproduce
1. Install the RNTester app on Android from the `main` branch.
2. Set the device auto-rotation to ON
3. Start the RNTester app
4. While the app is loading, rotate the device
5. Navigate to the `Dimensions` screen
6. Either
 a. Observe the screen width and height are reversed, or
 b. Quit the app and return to step 3.

### Verifying the fix

#### Manually
Using the above steps, the issue should no longer be reproducible.

#### Automatically
See unit tests in `ReactAndroid/src/test/java/com/facebook/react/modules/deviceinfo/DeviceInfoModuleTest.java`

### Video

https://user-images.githubusercontent.com/4940864/128485453-2ae04724-4ac5-4267-a59a-140cc3af626b.mp4

Reviewed By: JoshuaGross

Differential Revision: D30319919

Pulled By: lunaleaps

fbshipit-source-id: 52a2faeafc522b1c2a196ca40357027eafa1a84b

ReactAndroid/src/main/java/com/facebook/react/modules/deviceinfo/DeviceInfoModule.java

@@ -15,7 +15,7 @@ import com.facebook.react.bridge.ReactApplicationContext;
 import com.facebook.react.bridge.ReactNoCrashSoftException;
 import com.facebook.react.bridge.ReactSoftExceptionLogger;
 import com.facebook.react.bridge.ReadableMap;
-import com.facebook.react.bridge.WritableNativeMap;
+import com.facebook.react.bridge.WritableMap;
 import com.facebook.react.module.annotations.ReactModule;
 import com.facebook.react.modules.core.DeviceEventManagerModule;
 import com.facebook.react.uimanager.DisplayMetricsHolder;
@@ -54,8 +54,13 @@ public class DeviceInfoModule extends NativeDeviceInfoSpec implements LifecycleE
 
   @Override
   public @Nullable Map<String, Object> getTypedExportedConstants() {
+    WritableMap displayMetrics = DisplayMetricsHolder.getDisplayMetricsWritableMap(mFontScale);
+
+    // Cache the initial dimensions for later comparison in emitUpdateDimensionsEvent
+    mPreviousDisplayMetrics = displayMetrics.copy();
+
     HashMap<String, Object> constants = new HashMap<>();
-    constants.put("Dimensions", DisplayMetricsHolder.getDisplayMetricsMap(mFontScale));
+    constants.put("Dimensions", displayMetrics.toHashMap());
     return constants;
   }
 
@@ -85,8 +90,7 @@ public class DeviceInfoModule extends NativeDeviceInfoSpec implements LifecycleE
 
     if (mReactApplicationContext.hasActiveReactInstance()) {
       // Don't emit an event to JS if the dimensions haven't changed
-      WritableNativeMap displayMetrics =
-          DisplayMetricsHolder.getDisplayMetricsNativeMap(mFontScale);
+      WritableMap displayMetrics = DisplayMetricsHolder.getDisplayMetricsWritableMap(mFontScale);
       if (mPreviousDisplayMetrics == null) {
         mPreviousDisplayMetrics = displayMetrics.copy();
       } else if (!displayMetrics.equals(mPreviousDisplayMetrics)) {

ReactAndroid/src/main/java/com/facebook/react/uimanager/DisplayMetricsHolder.java

@@ -13,9 +13,8 @@ import android.view.Display;
 import android.view.WindowManager;
 import androidx.annotation.Nullable;
 import com.facebook.infer.annotation.Assertions;
+import com.facebook.react.bridge.WritableMap;
 import com.facebook.react.bridge.WritableNativeMap;
-import java.util.HashMap;
-import java.util.Map;
 
 /**
  * Holds an instance of the current DisplayMetrics so we don't have to thread it through all the
@@ -81,40 +80,20 @@ public class DisplayMetricsHolder {
     return sScreenDisplayMetrics;
   }
 
-  public static Map<String, Map<String, Object>> getDisplayMetricsMap(double fontScale) {
+  public static WritableMap getDisplayMetricsWritableMap(double fontScale) {
     Assertions.assertCondition(
         sWindowDisplayMetrics != null && sScreenDisplayMetrics != null,
-        "DisplayMetricsHolder must be initialized with initDisplayMetricsIfNotInitialized or initDisplayMetrics");
-    final Map<String, Map<String, Object>> result = new HashMap<>();
-    result.put("windowPhysicalPixels", getPhysicalPixelsMap(sWindowDisplayMetrics, fontScale));
-    result.put("screenPhysicalPixels", getPhysicalPixelsMap(sScreenDisplayMetrics, fontScale));
-    return result;
-  }
-
-  public static WritableNativeMap getDisplayMetricsNativeMap(double fontScale) {
-    Assertions.assertCondition(
-        sWindowDisplayMetrics != null && sScreenDisplayMetrics != null,
-        "DisplayMetricsHolder must be initialized with initDisplayMetricsIfNotInitialized or initDisplayMetrics");
+        "DisplayMetricsHolder must be initialized with initDisplayMetricsIfNotInitialized or"
+            + " initDisplayMetrics");
     final WritableNativeMap result = new WritableNativeMap();
     result.putMap(
-        "windowPhysicalPixels", getPhysicalPixelsNativeMap(sWindowDisplayMetrics, fontScale));
+        "windowPhysicalPixels", getPhysicalPixelsWritableMap(sWindowDisplayMetrics, fontScale));
     result.putMap(
-        "screenPhysicalPixels", getPhysicalPixelsNativeMap(sScreenDisplayMetrics, fontScale));
+        "screenPhysicalPixels", getPhysicalPixelsWritableMap(sScreenDisplayMetrics, fontScale));
     return result;
   }
 
-  private static Map<String, Object> getPhysicalPixelsMap(
-      DisplayMetrics displayMetrics, double fontScale) {
-    final Map<String, Object> result = new HashMap<>();
-    result.put("width", displayMetrics.widthPixels);
-    result.put("height", displayMetrics.heightPixels);
-    result.put("scale", displayMetrics.density);
-    result.put("fontScale", fontScale);
-    result.put("densityDpi", displayMetrics.densityDpi);
-    return result;
-  }
-
-  private static WritableNativeMap getPhysicalPixelsNativeMap(
+  private static WritableMap getPhysicalPixelsWritableMap(
       DisplayMetrics displayMetrics, double fontScale) {
     final WritableNativeMap result = new WritableNativeMap();
     result.putInt("width", displayMetrics.widthPixels);