Use scroll-boundary-behavior to control overscroll-refresh/glow on android.

content/browser/android/overscroll_controller_android.cc

Index: content/browser/android/overscroll_controller_android.cc
diff --git a/content/browser/android/overscroll_controller_android.cc b/content/browser/android/overscroll_controller_android.cc
index 3be50dac488ac9fdad7f86d83d778b8ef26cd3fd..60f6455790ccb96e8ad1db54cd91ad448c853789 100644
--- a/content/browser/android/overscroll_controller_android.cc
+++ b/content/browser/android/overscroll_controller_android.cc
@@ -95,6 +95,20 @@ std::unique_ptr<OverscrollRefresh> CreateRefreshEffect(
 
 }  // namespace
 
+OverscrollControllerAndroid::OverscrollControllerAndroid(
+    ui::OverscrollGlow* glow_effect,
+    ui::OverscrollRefresh* refresh_effect,
+    ui::WindowAndroidCompositor* compositor,
+    float dpi_scale)
+    : compositor_(compositor),
+      dpi_scale_(dpi_scale),
+      enabled_(true),
+      scroll_update_consumed_(false),
+      glow_effect_(glow_effect),
+      refresh_effect_(refresh_effect) {
+  DCHECK(compositor_);
+}
+
 OverscrollControllerAndroid::OverscrollControllerAndroid(
     ui::OverscrollRefreshHandler* overscroll_refresh_handler,
     ui::WindowAndroidCompositor* compositor,
@@ -102,6 +116,7 @@ OverscrollControllerAndroid::OverscrollControllerAndroid(
     : compositor_(compositor),
       dpi_scale_(dpi_scale),
       enabled_(true),
+      scroll_update_consumed_(false),
       glow_effect_(CreateGlowEffect(this, dpi_scale_)),
       refresh_effect_(CreateRefreshEffect(overscroll_refresh_handler)) {

[majidvp, 2017/07/12 21:04:20]

This constructor should delegate to the one above only
passing in newly created glow and refresh effects.

[sunyunjia, 2017/07/19 20:44:11]

Done. I'm not sure if the delegate is worth it. I have to initialize compositor_
and dpi_scale_ any way, as they are constants.

   DCHECK(compositor_);
@@ -128,6 +143,7 @@ bool OverscrollControllerAndroid::WillHandleGestureEvent(
   switch (event.GetType()) {
     case blink::WebInputEvent::kGestureScrollBegin:
       refresh_effect_->OnScrollBegin();
+      scroll_update_consumed_ = false;
       break;
 
     case blink::WebInputEvent::kGestureScrollUpdate: {
@@ -189,23 +205,49 @@ void OverscrollControllerAndroid::OnGestureEventAck(
       refresh_effect_) {
     // The effect should only be allowed if both the causal touch events go
     // unconsumed and the generated scroll events go unconsumed.
-    bool consumed =
+    scroll_update_consumed_ =
         ack_result == INPUT_EVENT_ACK_STATE_CONSUMED ||
         event.data.scroll_update.previous_update_in_sequence_prevented;
-    refresh_effect_->OnScrollUpdateAck(consumed);
   }
 }
 
 void OverscrollControllerAndroid::OnOverscrolled(
-    const DidOverscrollParams& params) {
+    const DidOverscrollParams& overscroll_params) {
   if (!enabled_)
     return;
 
-  if (refresh_effect_ && (refresh_effect_->IsActive() ||
-                          refresh_effect_->IsAwaitingScrollUpdateAck())) {
-    // An active (or potentially active) refresh effect should always pre-empt
-    // the passive glow effect.
-    return;
+  DidOverscrollParams params = overscroll_params;

[majidvp, 2017/07/12 21:04:20]

Seems a bit inefficient and unnecessary to create a copy of
whole params, reset some value conditionally and then copy
those values again to pass into the |glow_effect_->OnOverscrolled|.

Instead probably best to do

Vector2d accumulated_overscroll =
gfx::ScaleVector2d(overscroll_params.accumulated_overscroll, dpi_scale_);

if  (boundar_behavior = none)
  accumulated_overscroll.set_y(0);


glow_effect_->OnOverscrolled(..., accumulated_overscroll, ...)

[sunyunjia, 2017/07/19 20:44:11]

Done.

+
+  if (refresh_effect_) {
+    bool can_navigate =
+        (!scroll_update_consumed_) &&
+        (params.scroll_boundary_behavior.y ==
+         cc::ScrollBoundaryBehavior::ScrollBoundaryBehaviorType::
+             kScrollBoundaryBehaviorTypeAuto);
+    refresh_effect_->OnOverscrolled(can_navigate);
+
+    if (refresh_effect_->IsActive() ||
+        refresh_effect_->IsAwaitingScrollUpdateAck()) {
+      // An active (or potentially active) refresh effect should always pre-empt
+      // the passive glow effect.
+      return;
+    }
+  }
+
+  if (params.scroll_boundary_behavior.x ==
+      cc::ScrollBoundaryBehavior::ScrollBoundaryBehaviorType::
+          kScrollBoundaryBehaviorTypeNone) {
+    params.accumulated_overscroll.set_x(0);
+    params.latest_overscroll_delta.set_x(0);
+    params.current_fling_velocity.set_x(0);
+  }
+
+  if (params.scroll_boundary_behavior.y ==
+      cc::ScrollBoundaryBehavior::ScrollBoundaryBehaviorType::
+          kScrollBoundaryBehaviorTypeNone) {
+    params.accumulated_overscroll.set_y(0);
+    params.latest_overscroll_delta.set_y(0);
+    params.current_fling_velocity.set_y(0);
   }
 
   if (glow_effect_ &&