From 83d6a5ed8b428549d5966af2d535237e6cf61727 Mon Sep 17 00:00:00 2001
From: Jorim Jaggi <jjaggi@google.com>
Date: Mon, 10 Sep 2018 11:58:13 +0200
Subject: [PATCH] Only run layout if we didn't have content

Otherwise we really don't have to do it as showing the window will
not change whether we have content or not.

Test: Reopen app, ensure less layout runs
Test: Launch activity on virtual display.

Bug: 115577618
Bug: 112824998
Bug: 10154780

Change-Id: Id3bea85c93ead5e59f0456a2901378dd2c4a836f
Merged-In: Id3bea85c93ead5e59f0456a2901378dd2c4a836f
---
 .../com/android/server/wm/DisplayContent.java | 13 +++++++++++-
 .../server/wm/WindowStateAnimator.java        | 20 ++++++++++---------
 2 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/services/core/java/com/android/server/wm/DisplayContent.java b/services/core/java/com/android/server/wm/DisplayContent.java
index 2941e93d12dc8..22ac65df4337e 100644
--- a/services/core/java/com/android/server/wm/DisplayContent.java
+++ b/services/core/java/com/android/server/wm/DisplayContent.java
@@ -400,6 +400,9 @@ class DisplayContent extends WindowContainer<DisplayContent.DisplayChildWindowCo
 
     private MagnificationSpec mMagnificationSpec;
 
+    /** Caches the value whether told display manager that we have content. */
+    private boolean mLastHasContent;
+
     private final Consumer<WindowState> mUpdateWindowsForAnimator = w -> {
         WindowStateAnimator winAnimator = w.mWinAnimator;
         final AppWindowToken atoken = w.mAppToken;
@@ -2916,8 +2919,9 @@ class DisplayContent extends WindowContainer<DisplayContent.DisplayChildWindowCo
         forAllWindows(mApplySurfaceChangesTransaction, true /* traverseTopToBottom */);
         prepareSurfaces();
 
+        mLastHasContent = mTmpApplySurfaceChangesTransactionState.displayHasContent;
         mService.mDisplayManagerInternal.setDisplayProperties(mDisplayId,
-                mTmpApplySurfaceChangesTransactionState.displayHasContent,
+                mLastHasContent,
                 mTmpApplySurfaceChangesTransactionState.preferredRefreshRate,
                 mTmpApplySurfaceChangesTransactionState.preferredModeId,
                 true /* inTraversal, must call performTraversalInTrans... below */);
@@ -4052,4 +4056,11 @@ class DisplayContent extends WindowContainer<DisplayContent.DisplayChildWindowCo
     private boolean canUpdateImeTarget() {
         return mDeferUpdateImeTargetCount == 0;
     }
+
+    /**
+     * @return Cached value whether we told display manager that we have content.
+     */
+    boolean getLastHasContent() {
+        return mLastHasContent;
+    }
 }
diff --git a/services/core/java/com/android/server/wm/WindowStateAnimator.java b/services/core/java/com/android/server/wm/WindowStateAnimator.java
index 08b8150fbc6f6..c56c3035e1278 100644
--- a/services/core/java/com/android/server/wm/WindowStateAnimator.java
+++ b/services/core/java/com/android/server/wm/WindowStateAnimator.java
@@ -1185,15 +1185,17 @@ class WindowStateAnimator {
                         if (mIsWallpaper) {
                             w.dispatchWallpaperVisibility(true);
                         }
-                        // This draw means the difference between unique content and mirroring.
-                        // Run another pass through performLayout to set mHasContent in the
-                        // LogicalDisplay.
-                        mAnimator.setPendingLayoutChanges(w.getDisplayId(),
-                                FINISH_LAYOUT_REDO_ANIM);
-                        if (DEBUG_LAYOUT_REPEATS) {
-                            mService.mWindowPlacerLocked.debugLayoutRepeats(
-                                    "showSurfaceRobustlyLocked " + w,
-                                    mAnimator.getPendingLayoutChanges(w.getDisplayId()));
+                        if (!w.getDisplayContent().getLastHasContent()) {
+                            // This draw means the difference between unique content and mirroring.
+                            // Run another pass through performLayout to set mHasContent in the
+                            // LogicalDisplay.
+                            mAnimator.setPendingLayoutChanges(w.getDisplayId(),
+                                    FINISH_LAYOUT_REDO_ANIM);
+                            if (DEBUG_LAYOUT_REPEATS) {
+                                mService.mWindowPlacerLocked.debugLayoutRepeats(
+                                        "showSurfaceRobustlyLocked " + w,
+                                        mAnimator.getPendingLayoutChanges(w.getDisplayId()));
+                            }
                         }
                     } else {
                         w.setOrientationChanging(false);