ash: Fast ink damage fixes.

Limit damage rectangle to output rectangle and fix stationary point
generation and bounding box calculations for laser pointer to
make sure damage is reported correctly.

[email protected]

(cherry picked from commit 545a726)

Bug: 764007
Test: manual
Change-Id: Ie6352d539391776aa99ee00b7d1d302f0249e3dc
Reviewed-on: https://chromium-review.googlesource.com/668663
Commit-Queue: David Reveman <[email protected]>
Reviewed-by: Mitsuru Oshima <[email protected]>
Reviewed-by: Vladislav Kaznacheev <[email protected]>
Cr-Original-Commit-Position: refs/heads/master@{#502408}
Reviewed-on: https://chromium-review.googlesource.com/671868
Reviewed-by: David Reveman <[email protected]>
Cr-Commit-Position: refs/branch-heads/3202@{crosswalk-project#309}
Cr-Branched-From: fa6a5d8-refs/heads/master@{#499098}

ash/fast_ink/fast_ink_view.cc

@@ -359,11 +359,16 @@ void FastInkView::UpdateSurface() {
   gfx::Rect quad_rect(buffer_size);
   bool needs_blending = true;
 
+  gfx::Rect damage_rect(
+      gfx::ScaleToEnclosingRect(surface_damage_rect_, device_scale_factor));
+  surface_damage_rect_ = gfx::Rect();
+  // Constrain damage rectangle to output rectangle.
+  damage_rect.Intersect(output_rect);
+
   const int kRenderPassId = 1;
   std::unique_ptr<cc::RenderPass> render_pass = cc::RenderPass::Create();
-  render_pass->SetNew(kRenderPassId, output_rect, surface_damage_rect_,
+  render_pass->SetNew(kRenderPassId, output_rect, damage_rect,
                       buffer_to_target_transform);
-  surface_damage_rect_ = gfx::Rect();
 
   viz::SharedQuadState* quad_state =
       render_pass->CreateAndAppendSharedQuadState();

ash/laser/laser_pointer_view.cc

@@ -182,6 +182,7 @@ void LaserPointerView::AddNewPoint(const gfx::PointF& new_point,
                                       .Length())
                      : 0);
   AddPoint(new_point, new_time);
+  stationary_point_location_ = new_point;
   stationary_timer_->Reset();
 }
 
@@ -213,8 +214,7 @@ void LaserPointerView::FadeOut(const base::Closure& done) {
 void LaserPointerView::UpdateTime() {
   if (fadeout_done_.is_null()) {
     // Pointer still active but stationary, repeat the most recent position.
-    DCHECK(!laser_points_.IsEmpty());
-    AddPoint(laser_points_.GetNewest().location, ui::EventTimeForNow());
+    AddPoint(stationary_point_location_, ui::EventTimeForNow());
     return;
   }
 
@@ -237,10 +237,28 @@ void LaserPointerView::UpdateTime() {
 }
 
 gfx::Rect LaserPointerView::GetBoundingBox() {
+  // Early out if there are no points.
+  if (laser_points_.IsEmpty() && predicted_laser_points_.IsEmpty())
+    return gfx::Rect();
+
+  // Merge bounding boxes. Note that this is not a union as the bounding box
+  // for a single point is empty.
+  gfx::Rect bounding_box;
+  if (laser_points_.IsEmpty()) {
+    bounding_box = predicted_laser_points_.GetBoundingBox();
+  } else if (predicted_laser_points_.IsEmpty()) {
+    bounding_box = laser_points_.GetBoundingBox();
+  } else {
+    gfx::Rect rect = laser_points_.GetBoundingBox();
+    gfx::Rect predicted_rect = predicted_laser_points_.GetBoundingBox();
+    bounding_box.SetByBounds(std::min(predicted_rect.x(), rect.x()),
+                             std::min(predicted_rect.y(), rect.y()),
+                             std::max(predicted_rect.right(), rect.right()),
+                             std::max(predicted_rect.bottom(), rect.bottom()));
+  }
+
   // Expand the bounding box so that it includes the radius of the points on the
   // edges and antialiasing.
-  gfx::Rect bounding_box = laser_points_.GetBoundingBox();
-  bounding_box.Union(predicted_laser_points_.GetBoundingBox());
   const int kOutsetForAntialiasing = 1;
   int outset = kPointInitialRadius + kOutsetForAntialiasing;
   bounding_box.Inset(-outset, -outset);

ash/laser/laser_pointer_view.h

@@ -47,6 +47,7 @@ class LaserPointerView : public FastInkView {
   // Timer which will add a new stationary point when the stylus stops moving.
   // This will remove points that are too old.
   std::unique_ptr<base::Timer> stationary_timer_;
+  gfx::PointF stationary_point_location_;
 
   // A callback for when the fadeout is complete.
   base::Closure fadeout_done_;