ViewRootImpl: Guard against null in performMeasure

In particular we are seeing this in the call sites from performTraversals
in monkey crashes. I don't have exact repro but it seems like a feasible
state to get in to...for example...WindowManagerGlobal#addView can trigger
removal of a dying view immediately without respect for the mIsInTraversal
flag when it calls doDie(). This means we can dispatch detached from window
setting mView == null while performing a traversal. There's some question
about why this doDie is even required but...seems a little nerve wrecking
to change at the moment and it seems best to just guard against null for now.

Test: Monkeys will test.
Bug: 37343098
Change-Id: I94f2569c1ef70819c083f2b2b34b59622e6c6260

1 files changed, 3 insertions, 0 deletions

diff --git a/core/java/android/view/ViewRootImpl.java b/core/java/android/view/ViewRootImpl.java
index 1f13220289c2..f6cb30d40687 100644
--- a/core/java/android/view/ViewRootImpl.java
+++ b/core/java/android/view/ViewRootImpl.java
@@ -2410,6 +2410,9 @@ public final class ViewRootImpl implements ViewParent,
     }
 
     private void performMeasure(int childWidthMeasureSpec, int childHeightMeasureSpec) {
+        if (mView == null) {
+            return;
+        }
         Trace.traceBegin(Trace.TRACE_TAG_VIEW, "measure");
         try {
             mView.measure(childWidthMeasureSpec, childHeightMeasureSpec);