[Contextual Search] Remove layers when no longer needed.

chrome/android/java/src/org/chromium/chrome/browser/compositor/layouts/StaticLayout.java

Index: chrome/android/java/src/org/chromium/chrome/browser/compositor/layouts/StaticLayout.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/compositor/layouts/StaticLayout.java b/chrome/android/java/src/org/chromium/chrome/browser/compositor/layouts/StaticLayout.java
index 1cba75a1a3f7c657d518de31a1fc1c1934fcafbd..c6f5b721ab3058530df87e9b841d31de3fd228b8 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/compositor/layouts/StaticLayout.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/compositor/layouts/StaticLayout.java
@@ -254,6 +254,11 @@ public class StaticLayout extends ContextualSearchSupportedLayout {
     }
 
     @Override
+    public void detachViews() {
+        mSceneLayer.setContentSceneLayer(null);

[David Trainor- moved to gerrit, 2015/12/02 16:34:13]

Should we do this during hide or is this the only good hook for it?  IIRC this
was meant to attach/detach Android views to the view hierarchy (although
overriding it doesn't seem too dangerous for this particular scenario).

[pedro (no code reviews), 2015/12/02 23:56:14]

As we discussed offline, we need to remove the content scene layer every time
the Static Layout is hidden, but I couldn't find a better hook for it, given
that startHiding()/doneHiding() is not called when transitioning .

I'm including a TODO to revisit this later. For now, I think it's safer to keep
this code in here, since changing the system to dispatch
startHiding()/doneHiding() might have unexpected side effects.

+    }
+
+    @Override
     public void destroy() {
         if (mSceneLayer != null) {
             mSceneLayer.destroy();