Add overscroll edge effect animations for Android.

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 539e7d541158fb11373b6e3c60e60c2bcc2baf38..bbc5b38c2598a165517de979f5150c8d11736199 100644
--- a/content/browser/renderer_host/render_widget_host_view_android.cc
+++ b/content/browser/renderer_host/render_widget_host_view_android.cc
@@ -18,6 +18,7 @@
 #include "cc/output/compositor_frame.h"
 #include "cc/output/compositor_frame_ack.h"
 #include "content/browser/android/content_view_core_impl.h"
+#include "content/browser/android/overscroll_glow.h"
 #include "content/browser/gpu/gpu_surface_tracker.h"
 #include "content/browser/renderer_host/compositor_impl_android.h"
 #include "content/browser/renderer_host/image_transport_factory_android.h"
@@ -75,7 +76,7 @@ RenderWidgetHostViewAndroid::RenderWidgetHostViewAndroid(
     RenderWidgetHostImpl* widget_host,
     ContentViewCoreImpl* content_view_core)
     : host_(widget_host),
-      is_layer_attached_(true),
+      are_layers_attached_(true),
       content_view_core_(NULL),
       ime_adapter_android_(this),
       cached_background_color_(SK_ColorWHITE),
@@ -98,6 +99,11 @@ RenderWidgetHostViewAndroid::RenderWidgetHostViewAndroid(
 
   layer_->SetContentsOpaque(true);
 
+  if (CommandLine::ForCurrentProcess()->
+          HasSwitch(switches::kEnableOverscrollEdgeEffect)) {
+    overscroll_effect_ = OverscrollGlow::Create();
+  }
+
   host_->SetView(this);
   SetContentViewCore(content_view_core);
 }
@@ -292,6 +298,9 @@ void RenderWidgetHostViewAndroid::Blur() {
       host_->GetRoutingID(), "Unselect", ""));
   host_->SetInputMethodActive(false);
   host_->Blur();
+
+  if (overscroll_effect_)
+    overscroll_effect_->Finish();
 }
 
 bool RenderWidgetHostViewAndroid::HasFocus() const {
@@ -307,28 +316,26 @@ bool RenderWidgetHostViewAndroid::IsSurfaceAvailableForCopy() const {
 }
 
 void RenderWidgetHostViewAndroid::Show() {
-  if (is_layer_attached_)
+  if (are_layers_attached_)
     return;
 
-  is_layer_attached_ = true;
-  if (content_view_core_)
-    content_view_core_->AttachLayer(layer_);
+  are_layers_attached_ = true;
+  AttachLayers();
 }
 
 void RenderWidgetHostViewAndroid::Hide() {
-  if (!is_layer_attached_)
+  if (!are_layers_attached_)
     return;
 
-  is_layer_attached_ = false;
-  if (content_view_core_)
-    content_view_core_->RemoveLayer(layer_);
+  are_layers_attached_ = false;
+  RemoveLayers();
 }
 
 bool RenderWidgetHostViewAndroid::IsShowing() {
   // ContentViewCoreImpl represents the native side of the Java
   // ContentViewCore.  It being NULL means that it is not attached
   // to the View system yet, so we treat this RWHVA as hidden.
-  return is_layer_attached_ && content_view_core_;
+  return are_layers_attached_ && content_view_core_;
 }
 
 gfx::Rect RenderWidgetHostViewAndroid::GetViewBounds() const {
@@ -404,7 +411,8 @@ void RenderWidgetHostViewAndroid::OnDidChangeBodyBackgroundColor(
 }
 
 void RenderWidgetHostViewAndroid::SendVSync(base::TimeTicks frame_time) {
-  host_->Send(new ViewMsg_DidVSync(host_->GetRoutingID(), frame_time));
+  if (host_)
+    host_->Send(new ViewMsg_DidVSync(host_->GetRoutingID(), frame_time));
 }
 
 void RenderWidgetHostViewAndroid::OnSetVSyncNotificationEnabled(bool enabled) {
@@ -440,10 +448,8 @@ void RenderWidgetHostViewAndroid::RenderViewGone(
 }
 
 void RenderWidgetHostViewAndroid::Destroy() {
-  if (content_view_core_) {
-    content_view_core_->RemoveLayer(layer_);
-    content_view_core_ = NULL;
-  }
+  RemoveLayers();
+  content_view_core_ = NULL;
 
   // The RenderWidgetHost's destruction led here, so don't call it.
   host_ = NULL;
@@ -580,6 +586,8 @@ void RenderWidgetHostViewAndroid::ComputeContentsSize(
   content_size_in_layer_ =
       gfx::Size(texture_size_in_layer_.width() - offset.x(),
                 texture_size_in_layer_.height() - offset.y());
+  // Content size changes should be reflected in associated animation effects.
+  UpdateAnimationSize(frame);
 }
 
 void RenderWidgetHostViewAndroid::OnSwapCompositorFrame(
@@ -693,6 +701,52 @@ void RenderWidgetHostViewAndroid::BuffersSwapped(
     ack_callbacks_.push(ack_callback);
 }
 
+void RenderWidgetHostViewAndroid::AttachLayers() {
+  if (!content_view_core_)
+    return;
+
+  content_view_core_->AttachLayer(layer_);
+
+  if (overscroll_effect_)
+    overscroll_effect_->set_parent_layer(content_view_core_->GetLayer());

[no sievers, 2013/05/13 18:38:24]

Is it hard to change it so that it actually attaches it to the tree here (and
detaches below) rather than remembering a reference and attaching to the parent
at draw (or rather animate) time (see EdgeEffect::Draw())?

[jdduke (slow), 2013/05/13 20:44:24]

Yeah, I went back and forth on this as well.  The reasoning for the current
approach is that, as an EdgeEffect becomes dormant, it detaches its layers from
the parent layer.  ImageLayers (currently) can't clip themselves, so this
prevents RenderSurface promotion down the pipeline, and generally avoids
cluttering the layer tree.

So, either the EdgeEffect needs to cache its parent for when it's re-activated,
or OverscrollGlow needs to cache the parent and we just update it if necessary
at every Draw call.

The other thought I had was making an intermediate (but permanent) parent layer
in OverscrollGlow, and let RWHVA set the parent of that just like it sets the
parent of its owned layer_.

[no sievers, 2013/05/13 20:53:22]

And it doesn't work to just make it not drawable or so?

+}
+
+void RenderWidgetHostViewAndroid::RemoveLayers() {
+  if (!content_view_core_)
+    return;
+
+  if (overscroll_effect_)
+    overscroll_effect_->set_parent_layer(NULL);
+
+  content_view_core_->RemoveLayer(layer_);
+}
+
+bool RenderWidgetHostViewAndroid::Animate(base::TimeTicks frame_time) {
+  if (!overscroll_effect_ || !HasFocus())
+    return false;
+  return overscroll_effect_->Animate(frame_time);
+}
+
+void RenderWidgetHostViewAndroid::UpdateAnimationSize(
+    const cc::CompositorFrame* frame) {
+  if (!overscroll_effect_)
+    return;
+  // Disable edge effects for axes on which scrolling is impossible.
+  const cc::CompositorFrameMetadata& metadata = frame->metadata;
+  overscroll_effect_->set_horizontal_overscroll_enabled(
+      metadata.root_layer_size.width() != metadata.viewport_size.width());
+  overscroll_effect_->set_vertical_overscroll_enabled(
+      metadata.root_layer_size.height() != metadata.viewport_size.height());
+  overscroll_effect_->set_size(content_size_in_layer_);
+}
+
+void RenderWidgetHostViewAndroid::ScheduleAnimationIfNecessary() {
+  if (!content_view_core_)
+    return;
+  if (overscroll_effect_ && overscroll_effect_->IsActive())
+    content_view_core_->SetNeedsAnimate();
+}
+
 void RenderWidgetHostViewAndroid::AcceleratedSurfacePostSubBuffer(
     const GpuHostMsg_AcceleratedSurfacePostSubBuffer_Params& params,
     int gpu_host_id) {
@@ -875,16 +929,28 @@ SkColor RenderWidgetHostViewAndroid::GetCachedBackgroundColor() const {
   return cached_background_color_;
 }
 
+void RenderWidgetHostViewAndroid::OnOverscrolled(
+    const gfx::Vector2dF& accumulated_overscroll,
+    const gfx::Vector2dF& current_fling_velocity) {
+  if (!overscroll_effect_ || !HasFocus())
+    return;
+  overscroll_effect_->OnOverscrolled(base::TimeTicks::Now(),
+                                     accumulated_overscroll,
+                                     current_fling_velocity);
+  ScheduleAnimationIfNecessary();
+}
+
 void RenderWidgetHostViewAndroid::SetContentViewCore(
     ContentViewCoreImpl* content_view_core) {
   RunAckCallbacks();
 
-  if (content_view_core_ && is_layer_attached_)
-    content_view_core_->RemoveLayer(layer_);
+  if (are_layers_attached_)
+    RemoveLayers();
 
   content_view_core_ = content_view_core;
-  if (content_view_core_ && is_layer_attached_)
-    content_view_core_->AttachLayer(layer_);
+
+  if (are_layers_attached_)
+    AttachLayers();
 }
 
 void RenderWidgetHostViewAndroid::RunAckCallbacks() {