diff --git a/core/java/android/content/res/Configuration.java b/core/java/android/content/res/Configuration.java
index 417a95fbc4170..88c1627f955bc 100644
--- a/core/java/android/content/res/Configuration.java
+++ b/core/java/android/content/res/Configuration.java
@@ -16,7 +16,10 @@
 
 package android.content.res;
 
+import android.graphics.Point;
 import android.graphics.Rect;
+import android.util.DisplayMetrics;
+import android.view.Display;
 import android.view.DisplayInfo;
 import com.android.internal.util.XmlUtils;
 
@@ -42,12 +45,6 @@ import java.lang.annotation.RetentionPolicy;
 import java.util.ArrayList;
 import java.util.Locale;
 
-import static android.view.Surface.ROTATION_UNDEFINED;
-import static android.view.Surface.ROTATION_0;
-import static android.view.Surface.ROTATION_90;
-import static android.view.Surface.ROTATION_180;
-import static android.view.Surface.ROTATION_270;
-
 /**
  * This class describes all device configuration information that can
  * impact the resources the application retrieves.  This includes both
@@ -603,13 +600,6 @@ public final class Configuration implements Parcelable, Comparable<Configuration
      */
     public int orientation;
 
-    /**
-     * The rotation used at the time orientation was determined.
-     * TODO(b/36812336): Move rotation out of {@link Configuration}.
-     * {@hide}
-     */
-    private int rotation;
-
     /** Constant for {@link #uiMode}: bits that encode the mode type. */
     public static final int UI_MODE_TYPE_MASK = 0x0f;
     /** Constant for {@link #uiMode}: a {@link #UI_MODE_TYPE_MASK}
@@ -897,7 +887,6 @@ public final class Configuration implements Parcelable, Comparable<Configuration
         navigation = o.navigation;
         navigationHidden = o.navigationHidden;
         orientation = o.orientation;
-        rotation = o.rotation;
         screenLayout = o.screenLayout;
         colorMode = o.colorMode;
         uiMode = o.uiMode;
@@ -1001,14 +990,6 @@ public final class Configuration implements Parcelable, Comparable<Configuration
             case ORIENTATION_PORTRAIT: sb.append(" port"); break;
             default: sb.append(" orien="); sb.append(orientation); break;
         }
-        switch (rotation) {
-            case ROTATION_UNDEFINED: sb.append(" ?rotation"); break;
-            case ROTATION_0: sb.append(" rot0"); break;
-            case ROTATION_90: sb.append(" rot90"); break;
-            case ROTATION_180: sb.append(" rot180"); break;
-            case ROTATION_270: sb.append(" rot270"); break;
-            default: sb.append(" rot="); sb.append(rotation); break;
-        }
         switch ((uiMode&UI_MODE_TYPE_MASK)) {
             case UI_MODE_TYPE_UNDEFINED: sb.append(" ?uimode"); break;
             case UI_MODE_TYPE_NORMAL: /* normal is not interesting to print */ break;
@@ -1096,7 +1077,6 @@ public final class Configuration implements Parcelable, Comparable<Configuration
         navigation = NAVIGATION_UNDEFINED;
         navigationHidden = NAVIGATIONHIDDEN_UNDEFINED;
         orientation = ORIENTATION_UNDEFINED;
-        rotation = ROTATION_UNDEFINED;
         screenLayout = SCREENLAYOUT_UNDEFINED;
         colorMode = COLOR_MODE_UNDEFINED;
         uiMode = UI_MODE_TYPE_UNDEFINED;
@@ -1205,11 +1185,6 @@ public final class Configuration implements Parcelable, Comparable<Configuration
             changed |= ActivityInfo.CONFIG_ORIENTATION;
             orientation = delta.orientation;
         }
-        if (delta.rotation != ROTATION_UNDEFINED
-                && rotation != delta.rotation) {
-            changed |= ActivityInfo.CONFIG_ORIENTATION;
-            rotation = delta.rotation;
-        }
 
         if (((delta.screenLayout & SCREENLAYOUT_SIZE_MASK) != SCREENLAYOUT_SIZE_UNDEFINED)
                 && (delta.screenLayout & SCREENLAYOUT_SIZE_MASK)
@@ -1404,10 +1379,6 @@ public final class Configuration implements Parcelable, Comparable<Configuration
                 && orientation != delta.orientation) {
             changed |= ActivityInfo.CONFIG_ORIENTATION;
         }
-        if ((compareUndefined || delta.rotation != ROTATION_UNDEFINED)
-                && rotation != delta.rotation) {
-            changed |= ActivityInfo.CONFIG_ORIENTATION;
-        }
         if ((compareUndefined || getScreenLayoutNoDirection(delta.screenLayout) !=
                 (SCREENLAYOUT_SIZE_UNDEFINED | SCREENLAYOUT_LONG_UNDEFINED))
                 && getScreenLayoutNoDirection(screenLayout) !=
@@ -1544,7 +1515,6 @@ public final class Configuration implements Parcelable, Comparable<Configuration
         dest.writeInt(navigation);
         dest.writeInt(navigationHidden);
         dest.writeInt(orientation);
-        dest.writeInt(rotation);
         dest.writeInt(screenLayout);
         dest.writeInt(colorMode);
         dest.writeInt(uiMode);
@@ -1581,7 +1551,6 @@ public final class Configuration implements Parcelable, Comparable<Configuration
         navigation = source.readInt();
         navigationHidden = source.readInt();
         orientation = source.readInt();
-        rotation = source.readInt();
         screenLayout = source.readInt();
         colorMode = source.readInt();
         uiMode = source.readInt();
@@ -1666,8 +1635,6 @@ public final class Configuration implements Parcelable, Comparable<Configuration
         if (n != 0) return n;
         n = this.orientation - that.orientation;
         if (n != 0) return n;
-        n = this.rotation - that.rotation;
-        if (n != 0) return n;
         n = this.colorMode - that.colorMode;
         if (n != 0) return n;
         n = this.screenLayout - that.screenLayout;
@@ -1796,24 +1763,6 @@ public final class Configuration implements Parcelable, Comparable<Configuration
         appBounds.set(left, top, right, bottom);
     }
 
-    /**
-     * @hide
-     *
-     * Setter for orientation converts from {@link Surface} values to internal representation.
-     */
-    public void setRotation(int rotation) {
-        this.rotation = rotation;
-    }
-
-    /**
-     * @hide
-     *
-     * Getter for orientation. Converts from internal representation to  {@link Surface} values.
-     */
-    public int getRotation() {
-        return rotation != ROTATION_UNDEFINED ? rotation : ROTATION_0;
-    }
-
     /**
      * @hide
      *
@@ -2051,23 +2000,6 @@ public final class Configuration implements Parcelable, Comparable<Configuration
                 break;
         }
 
-        switch (config.rotation) {
-            case ROTATION_0:
-                parts.add("rot0");
-                break;
-            case ROTATION_90:
-                parts.add("rot90");
-                break;
-            case ROTATION_180:
-                parts.add("rot180");
-                break;
-            case ROTATION_270:
-                parts.add("rot270");
-                break;
-            default:
-                break;
-        }
-
         switch (config.uiMode & Configuration.UI_MODE_TYPE_MASK) {
             case Configuration.UI_MODE_TYPE_APPLIANCE:
                 parts.add("appliance");
@@ -2262,10 +2194,6 @@ public final class Configuration implements Parcelable, Comparable<Configuration
             delta.orientation = change.orientation;
         }
 
-        if (base.rotation != change.rotation) {
-            base.rotation = change.rotation;
-        }
-
         if ((base.screenLayout & SCREENLAYOUT_SIZE_MASK) !=
                 (change.screenLayout & SCREENLAYOUT_SIZE_MASK)) {
             delta.screenLayout |= change.screenLayout & SCREENLAYOUT_SIZE_MASK;
@@ -2337,7 +2265,6 @@ public final class Configuration implements Parcelable, Comparable<Configuration
     private static final String XML_ATTR_NAVIGATION = "nav";
     private static final String XML_ATTR_NAVIGATION_HIDDEN = "navHid";
     private static final String XML_ATTR_ORIENTATION = "ori";
-    private static final String XML_ATTR_ROTATION = "rot";
     private static final String XML_ATTR_SCREEN_LAYOUT = "scrLay";
     private static final String XML_ATTR_COLOR_MODE = "clrMod";
     private static final String XML_ATTR_UI_MODE = "ui";
@@ -2397,8 +2324,6 @@ public final class Configuration implements Parcelable, Comparable<Configuration
                 DENSITY_DPI_UNDEFINED);
         configOut.appBounds =
             Rect.unflattenFromString(XmlUtils.readStringAttribute(parser, XML_ATTR_APP_BOUNDS));
-        configOut.rotation = XmlUtils.readIntAttribute(parser, XML_ATTR_ROTATION,
-                ROTATION_UNDEFINED);
 
         // For persistence, we don't care about assetsSeq, so do not read it out.
     }
@@ -2475,10 +2400,6 @@ public final class Configuration implements Parcelable, Comparable<Configuration
                 config.appBounds.flattenToString());
         }
 
-        if (config.rotation != ROTATION_UNDEFINED) {
-            XmlUtils.writeIntAttribute(xml, XML_ATTR_ROTATION, config.rotation);
-        }
-
         // For persistence, we do not care about assetsSeq, so do not write it out.
     }
 }
diff --git a/core/java/android/view/IWindowSession.aidl b/core/java/android/view/IWindowSession.aidl
index 286e790554486..51d65144f2601 100644
--- a/core/java/android/view/IWindowSession.aidl
+++ b/core/java/android/view/IWindowSession.aidl
@@ -96,7 +96,7 @@ interface IWindowSession {
             int flags, out Rect outFrame, out Rect outOverscanInsets,
             out Rect outContentInsets, out Rect outVisibleInsets, out Rect outStableInsets,
             out Rect outOutsets, out Rect outBackdropFrame,
-            inout MergedConfiguration mergedConfiguration, out Surface outSurface);
+            out MergedConfiguration outMergedConfiguration, out Surface outSurface);
 
     /*
      * Notify the window manager that an application is relaunching and
diff --git a/core/java/android/view/Surface.java b/core/java/android/view/Surface.java
index 0ad591be2cf8c..8bb3fa988a45c 100644
--- a/core/java/android/view/Surface.java
+++ b/core/java/android/view/Surface.java
@@ -129,16 +129,10 @@ public class Surface implements Parcelable {
     public static final int SCALING_MODE_NO_SCALE_CROP = 3;
 
     /** @hide */
-    @IntDef({ROTATION_UNDEFINED, ROTATION_0, ROTATION_90, ROTATION_180, ROTATION_270})
+    @IntDef({ROTATION_0, ROTATION_90, ROTATION_180, ROTATION_270})
     @Retention(RetentionPolicy.SOURCE)
     public @interface Rotation {}
 
-    /**
-     * Rotation constant: undefined
-     * @hide
-     */
-    public static final int ROTATION_UNDEFINED = -1;
-
     /**
      * Rotation constant: 0 degree rotation (natural orientation)
      */
diff --git a/core/java/android/view/ViewRootImpl.java b/core/java/android/view/ViewRootImpl.java
index 19e0c95bc8148..2605b4a2e50c3 100644
--- a/core/java/android/view/ViewRootImpl.java
+++ b/core/java/android/view/ViewRootImpl.java
@@ -1845,12 +1845,8 @@ public final class ViewRootImpl implements ViewParent,
 
         final boolean isViewVisible = viewVisibility == View.VISIBLE;
         final boolean windowRelayoutWasForced = mForceNextWindowRelayout;
-        final int contextConfigSeq = mContext.getResources().getConfiguration().seq;
-        final int lastConfigSeq = mLastReportedMergedConfiguration.getMergedConfiguration().seq;
-        final boolean staleConfig = lastConfigSeq != 0 && contextConfigSeq != lastConfigSeq;
-
-        if (mFirst || windowShouldResize || insetsChanged || staleConfig || viewVisibilityChanged
-                || params != null || mForceNextWindowRelayout) {
+        if (mFirst || windowShouldResize || insetsChanged ||
+                viewVisibilityChanged || params != null || mForceNextWindowRelayout) {
             mForceNextWindowRelayout = false;
 
             if (isViewVisible) {
@@ -6087,13 +6083,7 @@ public final class ViewRootImpl implements ViewParent,
         if (params != null) {
             if (DBG) Log.d(mTag, "WindowLayout in layoutWindow:" + params);
         }
-
-        if (mPendingMergedConfiguration.getMergedConfiguration().seq == 0) {
-            mPendingMergedConfiguration.setTo(mLastReportedMergedConfiguration);
-        }
-
-        int initialConfigSeq = mPendingMergedConfiguration.getMergedConfiguration().seq;
-
+        mPendingMergedConfiguration.getMergedConfiguration().seq = 0;
         //Log.d(mTag, ">>>>>> CALLING relayout");
         if (params != null && mOrigWindowType != params.type) {
             // For compatibility with old apps, don't crash here.
@@ -6112,10 +6102,6 @@ public final class ViewRootImpl implements ViewParent,
                 mPendingStableInsets, mPendingOutsets, mPendingBackDropFrame,
                 mPendingMergedConfiguration, mSurface);
 
-        if (initialConfigSeq == mPendingMergedConfiguration.getMergedConfiguration().seq) {
-            mPendingMergedConfiguration.getMergedConfiguration().seq = 0;
-        }
-
         mPendingAlwaysConsumeNavBar =
                 (relayoutResult & WindowManagerGlobal.RELAYOUT_RES_CONSUME_ALWAYS_NAV_BAR) != 0;
 
diff --git a/services/core/java/com/android/server/wm/DisplayContent.java b/services/core/java/com/android/server/wm/DisplayContent.java
index a8e0d761afc39..ccc8f63e43557 100644
--- a/services/core/java/com/android/server/wm/DisplayContent.java
+++ b/services/core/java/com/android/server/wm/DisplayContent.java
@@ -1162,8 +1162,6 @@ class DisplayContent extends WindowContainer<DisplayContent.DisplayChildWindowCo
         final int dh = displayInfo.logicalHeight;
         config.orientation = (dw <= dh) ? Configuration.ORIENTATION_PORTRAIT :
                 Configuration.ORIENTATION_LANDSCAPE;
-        config.setRotation(displayInfo.rotation);
-
         config.screenWidthDp =
                 (int)(mService.mPolicy.getConfigDisplayWidth(dw, dh, displayInfo.rotation,
                         config.uiMode, mDisplayId) / mDisplayMetrics.density);
diff --git a/services/core/java/com/android/server/wm/WindowState.java b/services/core/java/com/android/server/wm/WindowState.java
index 1d08c2ec91514..f74948f8e7f06 100644
--- a/services/core/java/com/android/server/wm/WindowState.java
+++ b/services/core/java/com/android/server/wm/WindowState.java
@@ -2231,14 +2231,15 @@ class WindowState extends WindowContainer<WindowState> implements WindowManagerP
             mWinAnimator.applyEnterAnimationLocked();
         }
 
-        // always report back the new configuration
-        final Configuration globalConfig = mService.mRoot.getConfiguration();
-        final Configuration overrideConfig = getMergedOverrideConfiguration();
-        mergedConfiguration.setConfiguration(globalConfig, overrideConfig);
-        if (DEBUG_CONFIGURATION) Slog.i(TAG, "Window " + this
-                + " reporting new global config: " + globalConfig
-                + " merged override config: " + overrideConfig);
-        mLastReportedConfiguration.setTo(getConfiguration());
+        if (isConfigChanged()) {
+            final Configuration globalConfig = mService.mRoot.getConfiguration();
+            final Configuration overrideConfig = getMergedOverrideConfiguration();
+            mergedConfiguration.setConfiguration(globalConfig, overrideConfig);
+            if (DEBUG_CONFIGURATION) Slog.i(TAG, "Window " + this
+                    + " visible with new global config: " + globalConfig
+                    + " merged override config: " + overrideConfig);
+            mLastReportedConfiguration.setTo(getConfiguration());
+        }
     }
 
     void adjustStartingWindowFlags() {