Communicate whether passive event listeners exist to cc.

cc/layers/layer_impl.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/layers/layer_impl.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <utility>
@@ skipping 23 matching lines @@
 #include "cc/trees/layer_tree_settings.h"
 #include "cc/trees/proxy.h"
 #include "ui/gfx/geometry/box_f.h"
 #include "ui/gfx/geometry/point_conversions.h"
 #include "ui/gfx/geometry/quad_f.h"
 #include "ui/gfx/geometry/rect_conversions.h"
 #include "ui/gfx/geometry/size_conversions.h"
 #include "ui/gfx/geometry/vector2d_conversions.h"
 
 namespace cc {
+
+namespace {
+
+base::ListValue* EventListenerPropertiesAsJSON(
+    EventListenerProperties event_properties) {
+  base::ListValue* result = new base::ListValue;
+  if ((event_properties & EventListenerProperties::BLOCKING) !=
+      EventListenerProperties::NONE)
+    result->AppendString("Blocking");
+  if ((event_properties & EventListenerProperties::PASSIVE) !=
+      EventListenerProperties::NONE)
+    result->AppendString("Passive");
+  return result;
+}
+
+}  // namespace
+
 LayerImpl::LayerImpl(LayerTreeImpl* layer_impl, int id)
     : LayerImpl(layer_impl, id, new LayerImpl::SyncedScrollOffset) {
 }
 
 LayerImpl::LayerImpl(LayerTreeImpl* tree_impl,
                      int id,
                      scoped_refptr<SyncedScrollOffset> scroll_offset)
     : parent_(nullptr),
       scroll_parent_(nullptr),
       clip_parent_(nullptr),
       mask_layer_id_(-1),
       replica_layer_id_(-1),
       layer_id_(id),
       layer_tree_impl_(tree_impl),
       scroll_offset_(scroll_offset),
       scroll_clip_layer_id_(Layer::INVALID_ID),
       should_scroll_on_main_thread_(false),
-      have_wheel_event_handlers_(false),
       have_scroll_event_handlers_(false),
       scroll_blocks_on_(SCROLL_BLOCKS_ON_NONE),
       user_scrollable_horizontal_(true),
       user_scrollable_vertical_(true),
       stacking_order_changed_(false),
       double_sided_(true),
       should_flatten_transform_(true),
       should_flatten_transform_from_property_tree_(false),
       layer_property_changed_(false),
       masks_to_bounds_(false),
       contents_opaque_(false),
       is_root_for_isolated_group_(false),
       use_parent_backface_visibility_(false),
       draws_content_(false),
       hide_layer_and_subtree_(false),
       transform_is_invertible_(true),
       is_container_for_fixed_position_layers_(false),
       is_affected_by_page_scale_(true),
       was_ever_ready_since_last_transform_animation_(true),
+      touch_event_properties_(EventListenerProperties::NONE),
+      wheel_event_properties_(EventListenerProperties::NONE),
       background_color_(0),
       opacity_(1.0),
       blend_mode_(SkXfermode::kSrcOver_Mode),
       draw_blend_mode_(SkXfermode::kSrcOver_Mode),
       num_descendants_that_draw_content_(0),
       transform_tree_index_(-1),
       effect_tree_index_(-1),
       clip_tree_index_(-1),
       draw_depth_(0.f),
       needs_push_properties_(false),
@@ skipping 448 matching lines @@
     }
   }
 
   if (have_scroll_event_handlers() &&
       effective_block_mode & SCROLL_BLOCKS_ON_SCROLL_EVENT) {
     TRACE_EVENT0("cc", "LayerImpl::tryScroll: Failed ScrollEventHandlers");
     return InputHandler::SCROLL_ON_MAIN_THREAD;
   }
 
   if ((type == InputHandler::WHEEL || type == InputHandler::ANIMATED_WHEEL) &&
-      have_wheel_event_handlers() &&
+      wheel_event_properties() != EventListenerProperties::NONE &&
       effective_block_mode & SCROLL_BLOCKS_ON_WHEEL_EVENT) {
     TRACE_EVENT0("cc", "LayerImpl::tryScroll: Failed WheelEventHandlers");
     return InputHandler::SCROLL_ON_MAIN_THREAD;
   }
 
   if (!scrollable()) {
     TRACE_EVENT0("cc", "LayerImpl::tryScroll: Ignored not scrollable");
     return InputHandler::SCROLL_IGNORED;
   }
 
@@ skipping 28 matching lines @@
   // TODO(weiliangc): Should be safely removed after impl side is able to
   // update render surfaces without rebuilding property trees.
   if (layer->has_render_surface() != has_render_surface())
     layer->layer_tree_impl()->set_needs_update_draw_properties();
   layer->SetHasRenderSurface(!!render_surface());
   layer->SetForceRenderSurface(force_render_surface_);
   layer->SetFilters(filters());
   layer->SetBackgroundFilters(background_filters());
   layer->SetMasksToBounds(masks_to_bounds_);
   layer->SetShouldScrollOnMainThread(should_scroll_on_main_thread_);
-  layer->SetHaveWheelEventHandlers(have_wheel_event_handlers_);
+  layer->SetWheelEventProperties(wheel_event_properties_);

[aelias_OOO_until_Jul13, 2016/01/12 20:03:11]

I think we also need a SetTouchEventProperties call here too, or the property
will never make it past the pending tree?

[dtapuska, 2016/01/12 21:25:48]

Done.

   layer->SetHaveScrollEventHandlers(have_scroll_event_handlers_);
   layer->SetScrollBlocksOn(scroll_blocks_on_);
   layer->SetNonFastScrollableRegion(non_fast_scrollable_region_);
   layer->SetTouchEventHandlerRegion(touch_event_handler_region_);
   layer->SetContentsOpaque(contents_opaque_);
   layer->SetOpacity(opacity_);
   layer->SetBlendMode(blend_mode_);
   layer->SetIsRootForIsolatedGroup(is_root_for_isolated_group_);
   layer->SetPosition(position_);
   layer->SetIsContainerForFixedPositionLayers(
@@ skipping 130 matching lines @@
   result->Set("DrawTransform", list);
 
   result->SetBoolean("DrawsContent", draws_content_);
   result->SetBoolean("Is3dSorted", Is3dSorted());
   result->SetDouble("OPACITY", opacity());
   result->SetBoolean("ContentsOpaque", contents_opaque_);
 
   if (scrollable())
     result->SetBoolean("Scrollable", true);
 
-  if (have_wheel_event_handlers_)
-    result->SetBoolean("WheelHandler", have_wheel_event_handlers_);
+  if (touch_event_properties_ != EventListenerProperties::NONE) {
+    list = EventListenerPropertiesAsJSON(touch_event_properties_);
+    result->Set("TouchHandler", list);
+  }
+
+  if (wheel_event_properties_ != EventListenerProperties::NONE) {
+    list = EventListenerPropertiesAsJSON(wheel_event_properties_);
+    result->Set("WheelHandler", list);
+  }
+
   if (have_scroll_event_handlers_)
     result->SetBoolean("ScrollHandler", have_scroll_event_handlers_);
   if (!touch_event_handler_region_.IsEmpty()) {
     scoped_ptr<base::Value> region = touch_event_handler_region_.AsValue();
     result->Set("TouchRegion", region.release());
   }
 
   if (scroll_blocks_on_) {
     list = new base::ListValue;
     if (scroll_blocks_on_ & SCROLL_BLOCKS_ON_START_TOUCH)
@@ skipping 947 matching lines @@
   bool clipped;
   gfx::QuadF layer_quad =
       MathUtil::MapQuad(ScreenSpaceTransform(),
                         gfx::QuadF(gfx::RectF(gfx::Rect(bounds()))), &clipped);
   MathUtil::AddToTracedValue("layer_quad", layer_quad, state);
   if (!touch_event_handler_region_.IsEmpty()) {
     state->BeginArray("touch_event_handler_region");
     touch_event_handler_region_.AsValueInto(state);
     state->EndArray();
   }
-  if (have_wheel_event_handlers_) {
+  if (wheel_event_properties_ != EventListenerProperties::NONE) {
     gfx::Rect wheel_rect(bounds());
     Region wheel_region(wheel_rect);
     state->BeginArray("wheel_event_handler_region");
     wheel_region.AsValueInto(state);
     state->EndArray();
   }
   if (have_scroll_event_handlers_) {
     gfx::Rect scroll_rect(bounds());
     Region scroll_region(scroll_rect);
     state->BeginArray("scroll_event_handler_region");
@@ skipping 187 matching lines @@
            .layer_transforms_should_scale_layer_contents) {
     return default_scale;
   }
 
   gfx::Vector2dF transform_scales = MathUtil::ComputeTransform2dScaleComponents(
       DrawTransform(), default_scale);
   return std::max(transform_scales.x(), transform_scales.y());
 }
 
 }  // namespace cc