[CI] Remove broken IsSVG*Element overload

The:

 template<typename T> bool IsSVG*Element(const T*)

overload is a remnant after RawPtr<T>, but in its current form it would
only produce infinite recursion.

Also update some nearby documentation and rewrite the const Node&
overload to use the same form of condition as the other ones.

Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
Change-Id: Iecbc75423010bf26383dfd7504831bf1768a722d
Reviewed-on: https://chromium-review.googlesource.com/893270Reviewed-by: Stephen Chenney <schenney@chromium.org>
Commit-Queue: Fredrik Söderquist <fs@opera.com>
Cr-Commit-Position: refs/heads/master@{#533001}

third_party/WebKit/Source/core/svg/SVGElement.h

@@ -317,7 +317,7 @@ inline bool Node::HasTagName(const SVGQualifiedName& name) const {
   return IsSVGElement() && ToSVGElement(*this).HasTagName(name);
 }
 
-// This requires isSVG*Element(const SVGElement&).
+// This requires IsSVG*Element(const SVGElement&).
 #define DEFINE_SVGELEMENT_TYPE_CASTS_WITH_FUNCTION(thisType)               \
   inline bool Is##thisType(const thisType* element);                       \
   inline bool Is##thisType(const thisType& element);                       \
@@ -325,16 +325,12 @@ inline bool Node::HasTagName(const SVGQualifiedName& name) const {
     return element && Is##thisType(*element);                              \
   }                                                                        \
   inline bool Is##thisType(const Node& node) {                             \
-    return node.IsSVGElement() ? Is##thisType(ToSVGElement(node)) : false; \
+    return node.IsSVGElement() && Is##thisType(ToSVGElement(node));        \
   }                                                                        \
   inline bool Is##thisType(const Node* node) {                             \
     return node && Is##thisType(*node);                                    \
   }                                                                        \
   template <typename T>                                                    \
-  inline bool Is##thisType(const T* node) {                                \
-    return Is##thisType(node);                                             \
-  }                                                                        \
-  template <typename T>                                                    \
   inline bool Is##thisType(const Member<T>& node) {                        \
     return Is##thisType(node.Get());                                       \
   }                                                                        \