Fix a null pointer exception with nuked view while 2+ gestures in queue.

Bug: 1113758
Change-Id: I955a8031913e6acf1fe3c5b878e819a2d4a38fcf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2350560
Commit-Queue: Mustaq Ahmed <mustaq@chromium.org>
Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Cr-Commit-Position: refs/heads/master@{#797455}

content/browser/renderer_host/render_widget_host_impl.cc

@@ -514,6 +514,8 @@ RenderWidgetHostImpl* RenderWidgetHostImpl::From(RenderWidgetHost* rwh) {
 }
 
 void RenderWidgetHostImpl::SetView(RenderWidgetHostViewBase* view) {
+  synthetic_gesture_controller_.reset();
+
   if (view) {
     view_ = view->GetWeakPtr();
     if (!create_frame_sink_callback_.is_null())
@@ -521,8 +523,6 @@ void RenderWidgetHostImpl::SetView(RenderWidgetHostViewBase* view) {
   } else {
     view_.reset();
   }
-
-  synthetic_gesture_controller_.reset();
 }
 
 // static