Update from https://crrev.com/316786

cc/resources/picture_layer_tiling.cc

Index: cc/resources/picture_layer_tiling.cc
diff --git a/cc/resources/picture_layer_tiling.cc b/cc/resources/picture_layer_tiling.cc
index 033f9f6a7116ee1cf241885b4ae9d55ceeb2a07b..1e7281d6fdc4259f2f85eeacc93157b41884acb0 100644
--- a/cc/resources/picture_layer_tiling.cc
+++ b/cc/resources/picture_layer_tiling.cc
@@ -23,7 +23,8 @@
 namespace cc {
 namespace {
 
-const float kSoonBorderDistanceInScreenPixels = 312.f;
+const float kSoonBorderDistanceViewportPercentage = 0.15f;
+const float kMaxSoonBorderDistanceInScreenPixels = 312.f;
 
 }  // namespace
 
@@ -83,6 +84,17 @@ PictureLayerTiling::~PictureLayerTiling() {
     it->second->set_shared(false);
 }
 
+// static
+float PictureLayerTiling::CalculateSoonBorderDistance(
+    const gfx::Rect& visible_rect_in_content_space,
+    float content_to_screen_scale) {
+  float max_dimension = std::max(visible_rect_in_content_space.width(),
+                                 visible_rect_in_content_space.height());
+  return std::min(
+      kMaxSoonBorderDistanceInScreenPixels / content_to_screen_scale,
+      max_dimension * kSoonBorderDistanceViewportPercentage);
+}
+
 Tile* PictureLayerTiling::CreateTile(int i,
                                      int j,
                                      const PictureLayerTiling* twin_tiling,
@@ -605,7 +617,8 @@ bool PictureLayerTiling::ComputeTilePriorityRects(
   // Calculate the soon border rect.
   float content_to_screen_scale = ideal_contents_scale / contents_scale_;
   gfx::Rect soon_border_rect = visible_rect_in_content_space;
-  float border = kSoonBorderDistanceInScreenPixels / content_to_screen_scale;
+  float border = CalculateSoonBorderDistance(visible_rect_in_content_space,
+                                             content_to_screen_scale);
   soon_border_rect.Inset(-border, -border, -border, -border);
 
   last_impl_frame_time_in_seconds_ = current_frame_time_in_seconds;
@@ -866,7 +879,8 @@ void PictureLayerTiling::GetAllTilesForTracing(
     tiles->insert(it->second.get());
 }
 
-void PictureLayerTiling::AsValueInto(base::debug::TracedValue* state) const {
+void PictureLayerTiling::AsValueInto(
+    base::trace_event::TracedValue* state) const {
   state->SetInteger("num_tiles", tiles_.size());
   state->SetDouble("content_scale", contents_scale_);
   MathUtil::AddToTracedValue("tiling_size", tiling_size(), state);