Simplify the SVGTransformList.consolidate implementation

Since SVGTransformListTearOff::consolidate() is the business logic of
this method, we can implement the specific logic there rather than in
SVGTransformList. With that also drop the IsEmpty() check from

it return the resulting AffineTransform instead of using an out-
variable.

SVGTransformList: :Concatenate() - leaving that to the callers - and have
Change-Id: I25c80f7ae222f48fafecccd876a2cd79d57004e8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2218021Reviewed-by: Stephen Chenney <schenney@chromium.org>
Commit-Queue: Fredrik Söderquist <fs@opera.com>
Cr-Commit-Position: refs/heads/master@{#773093}

third_party/blink/renderer/core/svg/svg_svg_element.cc

@@ -670,15 +670,9 @@ AffineTransform SVGSVGElement::ViewBoxToViewTransform(float view_width,
       view_height);
   if (!view_spec_ || !view_spec_->Transform())
     return ctm;
-
   const SVGTransformList* transform_list = view_spec_->Transform();
-  if (transform_list->IsEmpty())
-    return ctm;
-
-  AffineTransform transform;
-  if (transform_list->Concatenate(transform))
-    ctm *= transform;
-
+  if (!transform_list->IsEmpty())
+    ctm *= transform_list->Concatenate();
   return ctm;
 }
 

third_party/blink/renderer/core/svg/svg_transform_list.cc

@@ -181,22 +181,11 @@ SVGTransformList::SVGTransformList(SVGTransformType transform_type,
 
 SVGTransformList::~SVGTransformList() = default;
 
-SVGTransform* SVGTransformList::Consolidate() {
-  AffineTransform matrix;
-  if (!Concatenate(matrix))
-    return nullptr;
-
-  return Initialize(MakeGarbageCollected<SVGTransform>(matrix));
-}
-
-bool SVGTransformList::Concatenate(AffineTransform& result) const {
-  if (IsEmpty())
-    return false;
-
+AffineTransform SVGTransformList::Concatenate() const {
+  AffineTransform result;
   for (const auto& item : *this)
     result *= item->Matrix();
-
-  return true;
+  return result;
 }
 
 namespace {

third_party/blink/renderer/core/svg/svg_transform_list.h

@@ -50,9 +50,7 @@ class SVGTransformList final
   SVGTransformList(SVGTransformType, const String&);
   ~SVGTransformList() override;
 
-  SVGTransform* Consolidate();
-
-  bool Concatenate(AffineTransform& result) const;
+  AffineTransform Concatenate() const;
 
   // SVGPropertyBase:
   SVGPropertyBase* CloneForAnimation(const String&) const override;

third_party/blink/renderer/core/svg/svg_transform_list_tear_off.cc

@@ -57,7 +57,13 @@ SVGTransformTearOff* SVGTransformListTearOff::consolidate(
     ThrowReadOnly(exception_state);
     return nullptr;
   }
-  return CreateItemTearOff(Target()->Consolidate());
+  SVGTransformList* transform_list = Target();
+  if (transform_list->IsEmpty())
+    return nullptr;
+  auto* concatenated_transform =
+      MakeGarbageCollected<SVGTransform>(transform_list->Concatenate());
+  transform_list->Initialize(concatenated_transform);
+  return CreateItemTearOff(concatenated_transform);
 }
 
 }  // namespace blink