diff --git a/core/java/android/view/ViewRootImpl.java b/core/java/android/view/ViewRootImpl.java
index 8f4a836b68614..ae8e43c4f6105 100644
--- a/core/java/android/view/ViewRootImpl.java
+++ b/core/java/android/view/ViewRootImpl.java
@@ -77,6 +77,7 @@ import static android.view.WindowManager.LayoutParams.SOFT_INPUT_ADJUST_RESIZE;
 import static android.view.WindowManager.LayoutParams.SOFT_INPUT_MASK_ADJUST;
 import static android.view.WindowManager.LayoutParams.TYPE_APPLICATION_STARTING;
 import static android.view.WindowManager.LayoutParams.TYPE_INPUT_METHOD;
+import static android.view.WindowManager.LayoutParams.TYPE_NOTIFICATION_SHADE;
 import static android.view.WindowManager.LayoutParams.TYPE_STATUS_BAR_ADDITIONAL;
 import static android.view.WindowManager.LayoutParams.TYPE_SYSTEM_ALERT;
 import static android.view.WindowManager.LayoutParams.TYPE_TOAST;
@@ -502,6 +503,13 @@ public final class ViewRootImpl implements ViewParent,
     Region mTouchableRegion;
     Region mPreviousTouchableRegion;
 
+    private int mMeasuredWidth;
+    private int mMeasuredHeight;
+
+    // This indicates that we've already known the window size but without measuring the views.
+    // If this is true, we must measure the views before laying out them.
+    private boolean mViewMeasureDeferred;
+
     @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.R, trackingBug = 170729553)
     int mWidth;
     @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.R, trackingBug = 170729553)
@@ -2557,7 +2565,8 @@ public final class ViewRootImpl implements ViewParent,
     }
 
     private boolean measureHierarchy(final View host, final WindowManager.LayoutParams lp,
-            final Resources res, final int desiredWindowWidth, final int desiredWindowHeight) {
+            final Resources res, final int desiredWindowWidth, final int desiredWindowHeight,
+            boolean forRootSizeOnly) {
         int childWidthMeasureSpec;
         int childHeightMeasureSpec;
         boolean windowSizeMayChange = false;
@@ -2613,7 +2622,15 @@ public final class ViewRootImpl implements ViewParent,
                     lp.privateFlags);
             childHeightMeasureSpec = getRootMeasureSpec(desiredWindowHeight, lp.height,
                     lp.privateFlags);
-            performMeasure(childWidthMeasureSpec, childHeightMeasureSpec);
+            if (!forRootSizeOnly || !setMeasuredRootSizeFromSpec(
+                    childWidthMeasureSpec, childHeightMeasureSpec)) {
+                performMeasure(childWidthMeasureSpec, childHeightMeasureSpec);
+            } else {
+                // We already know how big the window should be before measuring the views.
+                // We can measure the views before laying out them. This is to avoid unnecessary
+                // measure.
+                mViewMeasureDeferred = true;
+            }
             if (mWidth != host.getMeasuredWidth() || mHeight != host.getMeasuredHeight()) {
                 windowSizeMayChange = true;
             }
@@ -2628,6 +2645,25 @@ public final class ViewRootImpl implements ViewParent,
         return windowSizeMayChange;
     }
 
+    /**
+     * Sets the measured root size for requesting the window frame.
+     *
+     * @param widthMeasureSpec contains the size and the mode of the width.
+     * @param heightMeasureSpec contains the size and the mode of the height.
+     * @return {@code true} if we actually set the measured size; {@code false} otherwise.
+     */
+    private boolean setMeasuredRootSizeFromSpec(int widthMeasureSpec, int heightMeasureSpec) {
+        final int widthMode = MeasureSpec.getMode(widthMeasureSpec);
+        final int heightMode = MeasureSpec.getMode(heightMeasureSpec);
+        if (widthMode != MeasureSpec.EXACTLY || heightMode != MeasureSpec.EXACTLY) {
+            // We don't know the exact size. We need to measure the hierarchy to know that.
+            return false;
+        }
+        mMeasuredWidth = MeasureSpec.getSize(widthMeasureSpec);
+        mMeasuredHeight = MeasureSpec.getSize(heightMeasureSpec);
+        return true;
+    }
+
     /**
      * Modifies the input matrix such that it maps view-local coordinates to
      * on-screen coordinates.
@@ -2715,6 +2751,14 @@ public final class ViewRootImpl implements ViewParent,
                 || lp.type == TYPE_VOLUME_OVERLAY;
     }
 
+    /**
+     * @return {@code true} if we should reduce unnecessary measure for the window.
+     * TODO(b/260382739): Apply this to all windows.
+     */
+    private static boolean shouldOptimizeMeasure(final WindowManager.LayoutParams lp) {
+        return lp.type == TYPE_NOTIFICATION_SHADE;
+    }
+
     private Rect getWindowBoundsInsetSystemBars() {
         final Rect bounds = new Rect(
                 mContext.getResources().getConfiguration().windowConfiguration.getBounds());
@@ -2765,6 +2809,7 @@ public final class ViewRootImpl implements ViewParent,
         mAppVisibilityChanged = false;
         final boolean viewUserVisibilityChanged = !mFirst &&
                 ((mViewVisibility == View.VISIBLE) != (viewVisibility == View.VISIBLE));
+        final boolean shouldOptimizeMeasure = shouldOptimizeMeasure(lp);
 
         WindowManager.LayoutParams params = null;
         CompatibilityInfo compatibilityInfo =
@@ -2886,7 +2931,7 @@ public final class ViewRootImpl implements ViewParent,
 
             // Ask host how big it wants to be
             windowSizeMayChange |= measureHierarchy(host, lp, mView.getContext().getResources(),
-                    desiredWindowWidth, desiredWindowHeight);
+                    desiredWindowWidth, desiredWindowHeight, shouldOptimizeMeasure);
         }
 
         if (collectViewAttributes()) {
@@ -2926,8 +2971,8 @@ public final class ViewRootImpl implements ViewParent,
                 // we don't need to go through two layout passes when things
                 // change due to fitting system windows, which can happen a lot.
                 windowSizeMayChange |= measureHierarchy(host, lp,
-                        mView.getContext().getResources(),
-                        desiredWindowWidth, desiredWindowHeight);
+                        mView.getContext().getResources(), desiredWindowWidth, desiredWindowHeight,
+                        shouldOptimizeMeasure);
             }
         }
 
@@ -3342,6 +3387,13 @@ public final class ViewRootImpl implements ViewParent,
             maybeHandleWindowMove(frame);
         }
 
+        if (mViewMeasureDeferred) {
+            // It's time to measure the views since we are going to layout them.
+            performMeasure(
+                    MeasureSpec.makeMeasureSpec(frame.width(), MeasureSpec.EXACTLY),
+                    MeasureSpec.makeMeasureSpec(frame.height(), MeasureSpec.EXACTLY));
+        }
+
         if (!mRelayoutRequested && mCheckIfCanDraw) {
             // We had a sync previously, but we didn't call IWindowSession#relayout in this
             // traversal. So we don't know if the sync is complete that we can continue to draw.
@@ -3931,6 +3983,9 @@ public final class ViewRootImpl implements ViewParent,
         } finally {
             Trace.traceEnd(Trace.TRACE_TAG_VIEW);
         }
+        mMeasuredWidth = mView.getMeasuredWidth();
+        mMeasuredHeight = mView.getMeasuredHeight();
+        mViewMeasureDeferred = false;
     }
 
     /**
@@ -4026,7 +4081,7 @@ public final class ViewRootImpl implements ViewParent,
                         view.requestLayout();
                     }
                     measureHierarchy(host, lp, mView.getContext().getResources(),
-                            desiredWindowWidth, desiredWindowHeight);
+                            desiredWindowWidth, desiredWindowHeight, false /* forRootSizeOnly */);
                     mInLayout = true;
                     host.layout(0, 0, host.getMeasuredWidth(), host.getMeasuredHeight());
 
@@ -8092,8 +8147,8 @@ public final class ViewRootImpl implements ViewParent,
         final WindowConfiguration winConfigFromWm =
                 mLastReportedMergedConfiguration.getGlobalConfiguration().windowConfiguration;
         final WindowConfiguration winConfig = getCompatWindowConfiguration();
-        final int measuredWidth = mView.getMeasuredWidth();
-        final int measuredHeight = mView.getMeasuredHeight();
+        final int measuredWidth = mMeasuredWidth;
+        final int measuredHeight = mMeasuredHeight;
         final boolean relayoutAsync;
         if (LOCAL_LAYOUT
                 && (mViewFrameInfo.flags & FrameInfo.FLAG_WINDOW_VISIBILITY_CHANGED) == 0