Revert "[CSS] Treat viewport-relative units as computationally independent"

This is a speculative revert in order to either confirm or eliminate it
as a source for a hard to track down persistent performance regression.

This reverts r679183 (commit 6b846d36).

Bug: 993476
Tbr: pdr@chromium.org
Change-Id: I37566d32fb0853590e72299fdc0f281c712bf027
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1764195
Commit-Queue: Emil A Eklund <eae@chromium.org>
Reviewed-by: Emil A Eklund <eae@chromium.org>
Reviewed-by: Philip Rogers <pdr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#689475}

third_party/blink/renderer/core/css/css_numeric_literal_value.cc

@@ -126,14 +126,6 @@ bool CSSNumericLiteralValue::AccumulateLengthArray(CSSLengthArray& length_array,
   return true;
 }
 
-bool CSSNumericLiteralValue::IsComputationallyIndependent() const {
-  if (!IsLength())
-    return true;
-  if (IsViewportPercentageLength())
-    return true;
-  return !IsRelativeUnit(GetType());
-}
-
 static String FormatNumber(double number, const char* suffix) {
 #if defined(OS_WIN) && _MSC_VER < 1900
   unsigned oldFormat = _set_output_format(_TWO_DIGIT_EXPONENT);

third_party/blink/renderer/core/css/css_numeric_literal_value.h

@@ -47,7 +47,9 @@ class CORE_EXPORT CSSNumericLiteralValue : public CSSPrimitiveValue {
 
   bool IsZero() const { return !DoubleValue(); }
 
-  bool IsComputationallyIndependent() const;
+  bool IsComputationallyIndependent() const {
+    return !IsLength() || !IsRelativeUnit(GetType());
+  }
 
   double DoubleValue() const { return num_; }
   double ComputeSeconds() const;

third_party/blink/renderer/core/css/css_primitive_value.h

@@ -197,10 +197,9 @@ class CORE_EXPORT CSSPrimitiveValue : public CSSValue {
   static bool IsFlex(UnitType unit) { return unit == UnitType::kFraction; }
   bool IsFlex() const;
 
-  // https://drafts.css-houdini.org/css-properties-values-api-1/#computationally-independent
-  // A property value is computationally independent if it can be converted into
-  // a computed value using only the value of the property on the element, and
-  // "global" information that cannot be changed by CSS.
+  // Returns false when |this| is a length or a math function mixing percentage
+  // with length, and relative length units are involved. Returns true in all
+  // other cases.
   bool IsComputationallyIndependent() const;
 
   // Creates either a |CSSNumericLiteralValue| or a |CSSMathFunctionValue|,

third_party/blink/web_tests/external/wpt/css/css-properties-values-api/register-property-syntax-parsing.html

@@ -54,8 +54,6 @@ assert_valid("<percentage>", "-9.3e3%");
 assert_valid("<length-percentage>", "-54%");
 assert_valid("<length-percentage>", "0");
 assert_valid("<length-percentage>", "calc(-11px + 10.4%)");
-assert_valid("<length>", "10vmin");
-assert_valid("<percentage> | <length>+", "calc(100vh - 10px) 30px");
 
 assert_valid("<number>", "-109");
 assert_valid("<number>", "2.3e4");
@@ -185,12 +183,14 @@ assert_invalid("<length>", "10%");
 assert_invalid("<length>", "calc(5px + 10%)");
 assert_invalid("<length>", "calc(5px * 3px / 6px)");
 assert_invalid("<length>", "10em");
+assert_invalid("<length>", "10vmin");
 assert_invalid("<length>", "calc(4px + 3em)");
 assert_invalid("<length>", "calc(4px + calc(8 * 2em))");
 assert_invalid("<length>+", "calc(2ex + 16px)");
 assert_invalid("<length>+", "10px calc(20px + 4rem)");
 assert_invalid("<length>+", "");
 assert_invalid("<length>#", "");
+assert_invalid("<percentage> | <length>+", "calc(100vh - 10px) 30px");
 assert_invalid("<length>", "10px;");
 assert_invalid("<length-percentage>", "calc(2px + 10% + 7ex)");
 assert_invalid("<percentage>", "0");