Bug 1854404 - Remove global constructor in dom/html/input/InputType r=smaug

A constexpr variable is initialized at compile time and does not need a
global constructor.

Differential Revision: https://phabricator.services.mozilla.com/D188841

dom/html/input/InputType.cpp

@@ -24,7 +24,7 @@
 using namespace mozilla;
 using namespace mozilla::dom;
 
-const Decimal InputType::kStepAny = Decimal(0);
+constexpr Decimal InputType::kStepAny;
 
 /* static */ UniquePtr<InputType, InputType::DoNotDelete> InputType::Create(
     HTMLInputElement* aInputElement, FormControlType aType, void* aMemory) {

dom/html/input/InputType.h

@@ -48,7 +48,7 @@ class InputType {
   virtual ~InputType() = default;
 
   // Float value returned by GetStep() when the step attribute is set to 'any'.
-  static const Decimal kStepAny;
+  static constexpr Decimal kStepAny = Decimal(0_d);
 
   /**
    * Drop the reference to the input element.