Use default copy constructor for ComputedStyleBase.

third_party/WebKit/Source/build/scripts/templates/ComputedStyleBase.h.tmpl

 {% from 'macros.tmpl' import license, print_if %}
 {{license()}}
 
 #ifndef ComputedStyleBase_h
 #define ComputedStyleBase_h
 
 #include "core/ComputedStyleBaseConstants.h"
 #include "core/CoreExport.h"
 {% for path in include_paths %}
 #include "{{path}}"
@@ skipping 10 matching lines @@
 // The generated portion of ComputedStyle. For more info, see the header comment
 // in ComputedStyle.h.
 class CORE_EXPORT ComputedStyleBase {
  public:
   ALWAYS_INLINE ComputedStyleBase() :
   {% for field in fields %}
       {{field.name}}({{default_value(field)}}){{print_if(not loop.last, ',')}}
   {% endfor %}
   {}
 
-  ALWAYS_INLINE ComputedStyleBase(const ComputedStyleBase& o) :

[meade_UTC10, 2017/03/10 04:09:11]

Are we sure all the members of ComputedStyleBase will always all have their own
copy constructors? If any one of them doesn't, the compiler won't generate
this...

But - that might become a compile error in that case, where it wouldn't here, so
¯\_(ツ)_/¯

[shend, 2017/03/10 05:54:52]

Hopefully that won't happen :P Anyway, if one of the members is noncopyable,
this code will fail too since we're just calling the copy ctors of each member
right? To handle noncopyable members, we'd have to teach the generator how to
copy special fields, which is quite yuck.

-  {% for field in fields %}
-      {{field.name}}(o.{{field.name}}){{print_if(not loop.last, ',')}}
-  {% endfor %}
-  {}
-
   inline bool inheritedEqual(const ComputedStyleBase& o) const {
     return (
     {% for field in fields if field.is_property and field.is_inherited %}
         {{field.name}} == o.{{field.name}}{{print_if(not loop.last, ' &&')}}
     {% endfor %}
     );
   }
 
   inline bool independentInheritedEqual(const ComputedStyleBase& o) const {
     return (
@@ skipping 62 matching lines @@
  protected:
   // Storage.
   {% for field in fields %}
   unsigned {{field.name}} : {{field.size}}; // {{field.type_name}}
   {% endfor %}
 };
 
 } // namespace blink
 
 #endif // ComputedStyleBase_h