[CSS Typed OM] Make CSSRotation attributes mutable.

third_party/WebKit/Source/core/css/cssom/CSSRotation.cpp

Index: third_party/WebKit/Source/core/css/cssom/CSSRotation.cpp
diff --git a/third_party/WebKit/Source/core/css/cssom/CSSRotation.cpp b/third_party/WebKit/Source/core/css/cssom/CSSRotation.cpp
index c0ffda82a5d2fb8937f2169c01bab6501d78828b..0d8607f9096b3a12ea406816b8f8ab4e7b19a821 100644
--- a/third_party/WebKit/Source/core/css/cssom/CSSRotation.cpp
+++ b/third_party/WebKit/Source/core/css/cssom/CSSRotation.cpp
@@ -97,6 +97,19 @@ CSSRotation* CSSRotation::FromCSSValue(const CSSFunctionValue& value) {
   }
 }
 
+void CSSRotation::setAngle(CSSNumericValue* angle,
+                           ExceptionState& exception_state) {
+  if (angle->GetType() != CSSStyleValue::StyleValueType::kAngleType) {
+    exception_state.ThrowTypeError("Must pass an angle to CSSRotation");
+    return;
+  }
+  if (angle->IsCalculated()) {
+    exception_state.ThrowTypeError("Calculated angles are not supported yet");
+    return;
+  }
+  angle_ = angle;
+}
+
 CSSFunctionValue* CSSRotation::ToCSSValue() const {
   return nullptr;
   // TODO(meade): Re-implement this when we finish rewriting number/length