Add gfx::UnionRects() variant that takes a span of rects

Do this for gfx::Rect and gfx::RectF. Convert some existing code to use
the newly added helpers.

Change-Id: Ibe11b05199ddb8414f735777773d92a042fcd25a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5854921
Reviewed-by: Keren Zhu <kerenzhu@chromium.org>
Reviewed-by: Robert Flack <flackr@chromium.org>
Commit-Queue: Robert Flack <flackr@chromium.org>
Code-Coverage: findit-for-me@appspot.gserviceaccount.com <findit-for-me@appspot.gserviceaccount.com>
Auto-Submit: Lei Zhang <thestig@chromium.org>
Reviewed-by: danakj <danakj@chromium.org>
Reviewed-by: Akihiro Ota <akihiroota@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1354815}

ash/accessibility/ui/accessibility_highlight_layer.cc

@@ -39,10 +39,7 @@ void AccessibilityHighlightLayer::Set(const std::vector<gfx::Rect>& rects,
 
   // Calculate the bounds of all the rects together, that represents
   // the bounds of the full layer.
-  gfx::Rect bounds;
-  for (const gfx::Rect rect : rects_) {
-    bounds.Union(rect);
-  }
+  gfx::Rect bounds = gfx::UnionRects(rects_);
 
   int inset = kLayerMargin;
   bounds.Inset(-inset);

cc/base/invalidation_region.cc

@@ -39,15 +39,13 @@ void InvalidationRegion::FinalizePendingRects() {
   if (pending_rects_.empty())
     return;
 
+  gfx::Rect pending_bounds = gfx::UnionRects(pending_rects_);
   if (region_.GetRegionComplexity() + pending_rects_.size() >
       kMaxInvalidationRectCount) {
-    gfx::Rect pending_bounds = region_.bounds();
-    for (auto& rect : pending_rects_)
-      pending_bounds.Union(rect);
+    pending_bounds.Union(region_.bounds());
     region_ = pending_bounds;
   } else {
-    for (auto& rect : pending_rects_)
-      region_.Union(rect);
+    region_.Union(pending_bounds);
   }
 
   pending_rects_.clear();

components/ui_devtools/views/element_utility.cc

@@ -49,9 +49,7 @@ void AppendLayerPropertiesMatchedStyle(
 
   const ui::Layer::ShapeRects* alpha_shape_bounds = layer->alpha_shape();
   if (alpha_shape_bounds && alpha_shape_bounds->size()) {
-    gfx::Rect bounding_box;
-    for (auto& shape_bound : *alpha_shape_bounds)
-      bounding_box.Union(shape_bound);
+    gfx::Rect bounding_box = gfx::UnionRects(*alpha_shape_bounds);
     ret->emplace_back("alpha-shape-bounding-box", bounding_box.ToString());
   }
 

components/viz/service/display/dc_layer_overlay.cc

@@ -309,10 +309,8 @@ bool HasOccludingDamageRect(
   // surface_damage_rect_list[0] is the one on the very top.
   // surface_damage_rect_list[overlay_damage_index] is the damage rect of
   // this overlay surface.
-  gfx::Rect occluding_damage_rect;
-  for (size_t i = 0; i < overlay_damage_index; ++i) {
-    occluding_damage_rect.Union(surface_damage_rect_list[i]);
-  }
+  gfx::Rect occluding_damage_rect = gfx::UnionRects(
+      base::make_span(surface_damage_rect_list).first(overlay_damage_index));
   occluding_damage_rect.Intersect(quad_rect_in_target_space);
 
   return !occluding_damage_rect.IsEmpty();

pdf/pdfium/pdfium_engine.cc

@@ -2101,15 +2101,13 @@ bool PDFiumEngine::SelectFindResult(bool forward) {
   selection_.push_back(find_results_[current_find_index_.value()]);
 
   // If the result is not in view, scroll to it.
-  gfx::Rect bounding_rect;
   gfx::Rect visible_rect = GetVisibleRect();
 
   // Use zoom of 1.0 since `visible_rect` is without zoom.
   const std::vector<gfx::Rect>& rects =
       find_results_[current_find_index_.value()].GetScreenRects(
           gfx::Point(), 1.0, layout_.options().default_page_orientation());
-  for (const auto& rect : rects)
-    bounding_rect.Union(rect);
+  const gfx::Rect bounding_rect = gfx::UnionRects(rects);
   if (!visible_rect.Contains(bounding_rect)) {
     gfx::Point center = bounding_rect.CenterPoint();
     // Make the page centered.
@@ -2152,12 +2150,9 @@ std::vector<gfx::Rect> PDFiumEngine::GetAllScreenRectsUnion(
   std::vector<gfx::Rect> rect_vector;
   rect_vector.reserve(rect_range.size());
   for (const auto& range : rect_range) {
-    gfx::Rect result_rect;
     const std::vector<gfx::Rect>& rects = range.GetScreenRects(
         point, current_zoom_, layout_.options().default_page_orientation());
-    for (const auto& rect : rects)
-      result_rect.Union(rect);
-    rect_vector.push_back(result_rect);
+    rect_vector.push_back(gfx::UnionRects(rects));
   }
   return rect_vector;
 }

ui/gfx/geometry/rect.cc

@@ -344,6 +344,14 @@ Rect UnionRects(const Rect& a, const Rect& b) {
   return result;
 }
 
+Rect UnionRects(base::span<const Rect> rects) {
+  Rect result;
+  for (const Rect& rect : rects) {
+    result.Union(rect);
+  }
+  return result;
+}
+
 Rect UnionRectsEvenIfEmpty(const Rect& a, const Rect& b) {
   Rect result = a;
   result.UnionEvenIfEmpty(b);

ui/gfx/geometry/rect.h

@@ -16,7 +16,7 @@
 #include <iosfwd>
 #include <string>
 
-#include "base/check.h"
+#include "base/containers/span.h"
 #include "base/numerics/clamped_math.h"
 #include "base/numerics/safe_conversions.h"
 #include "build/build_config.h"
@@ -292,6 +292,7 @@ inline Rect operator+(const Vector2d& lhs, const Rect& rhs) {
 
 GEOMETRY_EXPORT Rect IntersectRects(const Rect& a, const Rect& b);
 GEOMETRY_EXPORT Rect UnionRects(const Rect& a, const Rect& b);
+GEOMETRY_EXPORT Rect UnionRects(base::span<const Rect> rects);
 GEOMETRY_EXPORT Rect UnionRectsEvenIfEmpty(const Rect& a, const Rect& b);
 GEOMETRY_EXPORT Rect SubtractRects(const Rect& a, const Rect& b);
 

ui/gfx/geometry/rect_f.cc

@@ -285,6 +285,14 @@ RectF UnionRects(const RectF& a, const RectF& b) {
   return result;
 }
 
+RectF UnionRects(base::span<const RectF> rects) {
+  RectF result;
+  for (const RectF& rect : rects) {
+    result.Union(rect);
+  }
+  return result;
+}
+
 RectF UnionRectsEvenIfEmpty(const RectF& a, const RectF& b) {
   RectF result = a;
   result.UnionEvenIfEmpty(b);

ui/gfx/geometry/rect_f.h

@@ -8,6 +8,7 @@
 #include <iosfwd>
 #include <string>
 
+#include "base/containers/span.h"
 #include "build/build_config.h"
 #include "ui/gfx/geometry/insets_f.h"
 #include "ui/gfx/geometry/outsets_f.h"
@@ -272,6 +273,7 @@ inline RectF operator+(const Vector2dF& lhs, const RectF& rhs) {
 
 GEOMETRY_EXPORT RectF IntersectRects(const RectF& a, const RectF& b);
 GEOMETRY_EXPORT RectF UnionRects(const RectF& a, const RectF& b);
+GEOMETRY_EXPORT RectF UnionRects(base::span<const RectF> rects);
 GEOMETRY_EXPORT RectF UnionRectsEvenIfEmpty(const RectF& a, const RectF& b);
 GEOMETRY_EXPORT RectF SubtractRects(const RectF& a, const RectF& b);