[Android] Add slack to allow refresh after overscrolling

content/browser/android/overscroll_glow.cc

Index: content/browser/android/overscroll_glow.cc
diff --git a/content/browser/android/overscroll_glow.cc b/content/browser/android/overscroll_glow.cc
index 4928d9f93453d3c2e60cb0781f2c514a509d4301..f7eb4bb9b0d92ba5199bfc161e81cbba22512d86 100644
--- a/content/browser/android/overscroll_glow.cc
+++ b/content/browser/android/overscroll_glow.cc
@@ -102,6 +102,15 @@ bool OverscrollGlow::IsActive() const {
   return false;
 }
 
+float OverscrollGlow::GetVisibleAlpha() const {
+  float max_alpha = 0;
+  for (size_t i = 0; i < EDGE_COUNT; ++i) {
+    if (!edge_effects_[i]->IsFinished())
+      max_alpha = std::max(max_alpha, edge_effects_[i]->GetAlpha());
+  }
+  return std::min(max_alpha, 1.f);
+}
+
 bool OverscrollGlow::OnOverscrolled(base::TimeTicks current_time,
                                     gfx::Vector2dF accumulated_overscroll,
                                     gfx::Vector2dF overscroll_delta,