Inline static Create() in some classes from renderer/core/css

Removes trivial Create() methods from classes defined in
renderer/core/css, and leaves non-trivial cases unchanged. Subdirs are
not included.

Affected classes: CSSRadialGradientValue, CSSImageValue,
CSSPendingSubstitutionValue, CSSQuadValue,
CSSStepsTimingFunctionValue, CSSURIValue, FontFaceSet, MediaQueryMatcher,
StyleRuleProperty and  StyleRuleNamespace.

Some highlights:

* Two constructors were added to CSSRadialGradientValue with the same
  list of parameters as the Create methods, to preserve the original
  semantics. One is intended to construct gradients with one center
  and a shape, and the other for gradients with two points.

* A constructor for CSSQuadValue which registers top, bottom, right
  and left to the same value was added to preserve the semantics of
  the original Create method, also to keep clients' legibility.

* A constructor for CSSURIValue with only one parameter was also added
  to preserve the semantics of the original Create method.

* The ternary operator ? from css_property_parser_helpers.cc was
  replaced with an if/then/else tree, because it cannot deduce the
  result type between CSSRadialGradientValue and
  CSSLinearGradientValue operators. This was not a problem before
  because one of the operators was of type CSSGradientValue.

* Create() methods for FontFaceSet, MediaQueryMatcher and
  StyleRuleNamespace were apparently unused.

Bug: 939691
Change-Id: I3e58b5a3560f794212ef4f87646524797f3ba079
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1954469
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Jacobo Aragunde Pérez <jaragunde@igalia.com>
Cr-Commit-Position: refs/heads/master@{#725051}
23 files changed