Mac overlays: Move CALayerPartialDamageTree to its own file

content/common/gpu/image_transport_surface_overlay_mac.mm

Index: content/common/gpu/image_transport_surface_overlay_mac.mm
diff --git a/content/common/gpu/image_transport_surface_overlay_mac.mm b/content/common/gpu/image_transport_surface_overlay_mac.mm
index 1b7236b5d9fc3f480d4d2903e2b7dd49a5ee9d57..16b1ccb7b05325f29b68ab63b8f496ac4da435c0 100644
--- a/content/common/gpu/image_transport_surface_overlay_mac.mm
+++ b/content/common/gpu/image_transport_surface_overlay_mac.mm
@@ -20,15 +20,13 @@
 typedef void* GLeglImageOES;
 #endif
 
-#include "base/command_line.h"
 #include "base/mac/scoped_cftyperef.h"
-#include "base/mac/sdk_forward_declarations.h"
+#include "content/common/gpu/ca_layer_partial_damage_tree_mac.h"
 #include "content/common/gpu/ca_layer_tree_mac.h"
 #include "content/common/gpu/gpu_messages.h"
 #include "ui/accelerated_widget_mac/io_surface_context.h"
 #include "ui/base/cocoa/animation_utils.h"
 #include "ui/base/cocoa/remote_layer_api.h"
-#include "ui/base/ui_base_switches.h"
 #include "ui/gfx/geometry/rect_conversions.h"
 #include "ui/gfx/transform.h"
 #include "ui/gl/gl_context.h"
@@ -59,16 +57,6 @@ const double kVSyncIntervalFractionForDisplayCallback = 0.5;
 // they come.
 const double kMaximumVSyncsBetweenSwapsForSmoothAnimation = 1.5;
 
-// When selecting a CALayer to re-use for partial damage, this is the maximum
-// fraction of the merged layer's pixels that may be not-updated by the swap
-// before we consider the CALayer to not be a good enough match, and create a
-// new one.
-const float kMaximumPartialDamageWasteFraction = 1.2f;
-
-// The maximum number of partial damage layers that may be created before we
-// give up and remove them all (doing full damage in the process).
-const size_t kMaximumPartialDamageLayers = 8;
-
 void CheckGLErrors(const char* msg) {
   GLenum gl_error;
   while ((gl_error = glGetError()) != GL_NO_ERROR) {
@@ -94,114 +82,6 @@ scoped_refptr<gfx::GLSurface> ImageTransportSurfaceCreateNativeSurface(
   return new ImageTransportSurfaceOverlayMac(manager, stub, handle);
 }
 
-class CALayerPartialDamageTree {
- public:
-  CALayerPartialDamageTree(bool allow_partial_swap,
-                           base::ScopedCFTypeRef<IOSurfaceRef> io_surface,
-                           const gfx::Rect& pixel_frame_rect);
-  ~CALayerPartialDamageTree();
-
-  base::ScopedCFTypeRef<IOSurfaceRef> RootLayerIOSurface();
-  void CommitCALayers(CALayer* superlayer,
-                      scoped_ptr<CALayerPartialDamageTree> old_tree,
-                      float scale_factor,
-                      const gfx::Rect& pixel_damage_rect);
-
- private:
-  class OverlayPlane;
-
-  void UpdateRootAndPartialDamagePlanes(CALayerPartialDamageTree* old_tree,
-                                        const gfx::RectF& pixel_damage_rect);
-  void UpdateRootAndPartialDamageCALayers(CALayer* superlayer,
-                                          float scale_factor);
-
-  const bool allow_partial_swap_;
-  linked_ptr<OverlayPlane> root_plane_;
-  std::list<linked_ptr<OverlayPlane>> partial_damage_planes_;
-};
-
-class CALayerPartialDamageTree::OverlayPlane {
- public:
-  static linked_ptr<OverlayPlane> CreateWithFrameRect(
-      int z_order,
-      base::ScopedCFTypeRef<IOSurfaceRef> io_surface,
-      const gfx::RectF& pixel_frame_rect,
-      const gfx::RectF& contents_rect) {
-    gfx::Transform transform;
-    transform.Translate(pixel_frame_rect.x(), pixel_frame_rect.y());
-    return linked_ptr<OverlayPlane>(
-        new OverlayPlane(z_order, io_surface, contents_rect, pixel_frame_rect));
-  }
-
-  ~OverlayPlane() {
-    [ca_layer setContents:nil];
-    [ca_layer removeFromSuperlayer];
-    ca_layer.reset();
-  }
-
-  const int z_order;
-  const base::ScopedCFTypeRef<IOSurfaceRef> io_surface;
-  const gfx::RectF contents_rect;
-  const gfx::RectF pixel_frame_rect;
-  bool layer_needs_update;
-  base::scoped_nsobject<CALayer> ca_layer;
-
-  void TakeCALayerFrom(OverlayPlane* other_plane) {
-    ca_layer.swap(other_plane->ca_layer);
-  }
-
-  void UpdateProperties(float scale_factor) {
-    if (layer_needs_update) {
-      [ca_layer setOpaque:YES];
-
-      id new_contents = static_cast<id>(io_surface.get());
-      if ([ca_layer contents] == new_contents && z_order == 0)
-        [ca_layer setContentsChanged];
-      else
-        [ca_layer setContents:new_contents];
-      [ca_layer setContentsRect:contents_rect.ToCGRect()];
-
-      [ca_layer setAnchorPoint:CGPointZero];
-
-      if ([ca_layer respondsToSelector:(@selector(setContentsScale:))])
-        [ca_layer setContentsScale:scale_factor];
-      gfx::RectF dip_frame_rect = gfx::RectF(pixel_frame_rect);
-      dip_frame_rect.Scale(1 / scale_factor);
-      [ca_layer setBounds:CGRectMake(0, 0, dip_frame_rect.width(),
-                                     dip_frame_rect.height())];
-      [ca_layer
-          setPosition:CGPointMake(dip_frame_rect.x(), dip_frame_rect.y())];
-    }
-    static bool show_borders =
-        base::CommandLine::ForCurrentProcess()->HasSwitch(
-            switches::kShowMacOverlayBorders);
-    if (show_borders) {
-      base::ScopedCFTypeRef<CGColorRef> color;
-      if (!layer_needs_update) {
-        // Green represents contents that are unchanged across frames.
-        color.reset(CGColorCreateGenericRGB(0, 1, 0, 1));
-      } else {
-        // Red represents damaged contents.
-        color.reset(CGColorCreateGenericRGB(1, 0, 0, 1));
-      }
-      [ca_layer setBorderWidth:1];
-      [ca_layer setBorderColor:color];
-    }
-    layer_needs_update = false;
-  }
-
- private:
-  OverlayPlane(int z_order,
-               base::ScopedCFTypeRef<IOSurfaceRef> io_surface,
-               const gfx::RectF& contents_rect,
-               const gfx::RectF& pixel_frame_rect)
-      : z_order(z_order),
-        io_surface(io_surface),
-        contents_rect(contents_rect),
-        pixel_frame_rect(pixel_frame_rect),
-        layer_needs_update(true) {}
-};
-
 class ImageTransportSurfaceOverlayMac::PendingSwap {
  public:
   PendingSwap() {}
@@ -441,135 +321,6 @@ void ImageTransportSurfaceOverlayMac::DisplayFirstPendingSwapImmediately() {
   pending_swaps_.pop_front();
 }
 
-void CALayerPartialDamageTree::UpdateRootAndPartialDamagePlanes(
-    CALayerPartialDamageTree* old_tree,
-    const gfx::RectF& pixel_damage_rect) {
-  // This is the plane that will be updated this frame. It may be the root plane
-  // or a child plane.
-  linked_ptr<OverlayPlane> plane_for_swap;
-
-  // If the frame's size changed, if we haven't updated the root layer, if
-  // we have full damage, or if we don't support remote layers, then use the
-  // root layer directly.
-  if (!allow_partial_swap_ || !old_tree ||
-      old_tree->root_plane_->pixel_frame_rect !=
-          root_plane_->pixel_frame_rect ||
-      pixel_damage_rect == root_plane_->pixel_frame_rect) {
-    plane_for_swap = root_plane_;
-  }
-
-  // Walk though the old tree's partial damage layers and see if there is one
-  // that is appropriate to re-use.
-  if (!plane_for_swap.get() && !pixel_damage_rect.IsEmpty()) {
-    gfx::RectF plane_to_reuse_dip_enlarged_rect;
-
-    // Find the last partial damage plane to re-use the CALayer from. Grow the
-    // new rect for this layer to include this damage, and all nearby partial
-    // damage layers.
-    linked_ptr<OverlayPlane> plane_to_reuse;
-    for (auto& old_plane : old_tree->partial_damage_planes_) {
-      gfx::RectF dip_enlarged_rect = old_plane->pixel_frame_rect;
-      dip_enlarged_rect.Union(pixel_damage_rect);
-
-      // Compute the fraction of the pixels that would not be updated by this
-      // swap. If it is too big, try another layer.
-      float waste_fraction = dip_enlarged_rect.size().GetArea() * 1.f /
-                             pixel_damage_rect.size().GetArea();
-      if (waste_fraction > kMaximumPartialDamageWasteFraction)
-        continue;
-
-      plane_to_reuse = old_plane;
-      plane_to_reuse_dip_enlarged_rect.Union(dip_enlarged_rect);
-    }
-
-    if (plane_to_reuse.get()) {
-      gfx::RectF enlarged_contents_rect = plane_to_reuse_dip_enlarged_rect;
-      enlarged_contents_rect.Scale(1. / root_plane_->pixel_frame_rect.width(),
-                                   1. / root_plane_->pixel_frame_rect.height());
-
-      plane_for_swap = OverlayPlane::CreateWithFrameRect(
-          0, root_plane_->io_surface, plane_to_reuse_dip_enlarged_rect,
-          enlarged_contents_rect);
-
-      plane_for_swap->TakeCALayerFrom(plane_to_reuse.get());
-      if (plane_to_reuse != old_tree->partial_damage_planes_.back())
-        [plane_for_swap->ca_layer removeFromSuperlayer];
-    }
-  }
-
-  // If we haven't found an appropriate layer to re-use, create a new one, if
-  // we haven't already created too many.
-  if (!plane_for_swap.get() && !pixel_damage_rect.IsEmpty() &&
-      old_tree->partial_damage_planes_.size() < kMaximumPartialDamageLayers) {
-    gfx::RectF contents_rect = gfx::RectF(pixel_damage_rect);
-    contents_rect.Scale(1. / root_plane_->pixel_frame_rect.width(),
-                        1. / root_plane_->pixel_frame_rect.height());
-    plane_for_swap = OverlayPlane::CreateWithFrameRect(
-        0, root_plane_->io_surface, pixel_damage_rect, contents_rect);
-  }
-
-  // And if we still don't have a layer, use the root layer.
-  if (!plane_for_swap.get() && !pixel_damage_rect.IsEmpty())
-    plane_for_swap = root_plane_;
-
-  // Walk all old partial damage planes. Remove anything that is now completely
-  // covered, and move everything else into the new |partial_damage_planes_|.
-  if (old_tree) {
-    for (auto& old_plane : old_tree->partial_damage_planes_) {
-      // Intersect the planes' frames with the new root plane to ensure that
-      // they don't get kept alive inappropriately.
-      gfx::RectF old_plane_frame_rect = old_plane->pixel_frame_rect;
-      old_plane_frame_rect.Intersect(root_plane_->pixel_frame_rect);
-
-      bool old_plane_covered_by_swap = false;
-      if (plane_for_swap.get() &&
-          plane_for_swap->pixel_frame_rect.Contains(old_plane_frame_rect)) {
-        old_plane_covered_by_swap = true;
-      }
-      if (!old_plane_covered_by_swap) {
-        DCHECK(old_plane->ca_layer);
-        partial_damage_planes_.push_back(old_plane);
-      }
-    }
-    if (plane_for_swap != root_plane_)
-      root_plane_ = old_tree->root_plane_;
-  }
-
-  // Finally, add the new swap's plane at the back of the list, if it exists.
-  if (plane_for_swap.get() && plane_for_swap != root_plane_) {
-    partial_damage_planes_.push_back(plane_for_swap);
-  }
-}
-
-void CALayerPartialDamageTree::UpdateRootAndPartialDamageCALayers(
-    CALayer* superlayer,
-    float scale_factor) {
-  if (!allow_partial_swap_) {
-    DCHECK(partial_damage_planes_.empty());
-    return;
-  }
-
-  // Allocate and update CALayers for the backbuffer and partial damage layers.
-  if (!root_plane_->ca_layer) {
-    root_plane_->ca_layer.reset([[CALayer alloc] init]);
-    [superlayer setSublayers:nil];
-    [superlayer addSublayer:root_plane_->ca_layer];
-  }
-  for (auto& plane : partial_damage_planes_) {
-    if (!plane->ca_layer) {
-      DCHECK(plane == partial_damage_planes_.back());
-      plane->ca_layer.reset([[CALayer alloc] init]);
-    }
-    if (![plane->ca_layer superlayer]) {
-      DCHECK(plane == partial_damage_planes_.back());
-      [superlayer addSublayer:plane->ca_layer];
-    }
-  }
-  root_plane_->UpdateProperties(scale_factor);
-  for (auto& plane : partial_damage_planes_)
-    plane->UpdateProperties(scale_factor);
-}
-
 void ImageTransportSurfaceOverlayMac::DisplayAndClearAllPendingSwaps() {
   TRACE_EVENT0("gpu",
       "ImageTransportSurfaceOverlayMac::DisplayAndClearAllPendingSwaps");
@@ -765,30 +516,4 @@ base::TimeTicks ImageTransportSurfaceOverlayMac::GetNextVSyncTimeAfter(
   return previous_vsync + (1 + interval_fraction) * vsync_interval_;
 }
 
-CALayerPartialDamageTree::CALayerPartialDamageTree(
-    bool allow_partial_swap,
-    base::ScopedCFTypeRef<IOSurfaceRef> io_surface,
-    const gfx::Rect& pixel_frame_rect)
-    : allow_partial_swap_(allow_partial_swap) {
-  root_plane_ = OverlayPlane::CreateWithFrameRect(
-      0, io_surface, gfx::RectF(pixel_frame_rect), gfx::RectF(0, 0, 1, 1));
-}
-
-CALayerPartialDamageTree::~CALayerPartialDamageTree() {}
-
-base::ScopedCFTypeRef<IOSurfaceRef>
-CALayerPartialDamageTree::RootLayerIOSurface() {
-  return root_plane_->io_surface;
-}
-
-void CALayerPartialDamageTree::CommitCALayers(
-    CALayer* superlayer,
-    scoped_ptr<CALayerPartialDamageTree> old_tree,
-    float scale_factor,
-    const gfx::Rect& pixel_damage_rect) {
-  UpdateRootAndPartialDamagePlanes(old_tree.get(),
-                                   gfx::RectF(pixel_damage_rect));
-  UpdateRootAndPartialDamageCALayers(superlayer, scale_factor);
-}
-
 }  // namespace content