[Android] Speculative fix for crash during overscroll effect creation

content/browser/renderer_host/render_widget_host_view_android.cc

Index: content/browser/renderer_host/render_widget_host_view_android.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_android.cc b/content/browser/renderer_host/render_widget_host_view_android.cc
index ed0e60fcdc845085190029e01b8af3f121b1f87a..5ac9d834e8a4016e48b1cb50bde18f0cbc6219fd 100644
--- a/content/browser/renderer_host/render_widget_host_view_android.cc
+++ b/content/browser/renderer_host/render_widget_host_view_android.cc
@@ -1547,6 +1547,7 @@ void RenderWidgetHostViewAndroid::SetContentViewCore(
 
   bool resize = false;
   if (content_view_core != content_view_core_) {
+    overscroll_effect_.reset();
     selection_controller_.reset();
     ReleaseLocksOnSurface();
     resize = true;
@@ -1577,9 +1578,8 @@ void RenderWidgetHostViewAndroid::SetContentViewCore(
   if (!selection_controller_)
     selection_controller_.reset(new TouchSelectionController(this));
 
-  if (!content_view_core_)
-    overscroll_effect_.reset();
-  else if (overscroll_effect_enabled_ && !overscroll_effect_)
+  if (overscroll_effect_enabled_ && !overscroll_effect_ &&
+      content_view_core_->GetWindowAndroid()->GetCompositor())
     overscroll_effect_ = CreateOverscrollEffect(content_view_core_);
 }
 
@@ -1602,10 +1602,18 @@ void RenderWidgetHostViewAndroid::OnCompositingDidCommit() {
   RunAckCallbacks();
 }
 
+
+void RenderWidgetHostViewAndroid::OnAttachCompositor() {
+  DCHECK(content_view_core_);
+  if (overscroll_effect_enabled_ && !overscroll_effect_)
+    overscroll_effect_ = CreateOverscrollEffect(content_view_core_);
+}
+
 void RenderWidgetHostViewAndroid::OnDetachCompositor() {
   DCHECK(content_view_core_);
   DCHECK(!using_synchronous_compositor_);
   RunAckCallbacks();
+  overscroll_effect_.reset();
 }
 
 void RenderWidgetHostViewAndroid::OnVSync(base::TimeTicks frame_time,