Consolidate read-only exception throwing for SVG*TearOffs

third_party/WebKit/Source/core/svg/SVGMatrixTearOff.cpp

 /*
  * Copyright (C) 2014 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 59 matching lines @@
         return;
 
     m_contextTransform->target()->onMatrixChange();
     m_contextTransform->commitChange();
 }
 
 #define DEFINE_SETTER(ATTRIBUTE) \
     void SVGMatrixTearOff::set##ATTRIBUTE(double f, ExceptionState& exceptionState) \
     { \
         if (m_contextTransform && m_contextTransform->isImmutable()) { \
-            exceptionState.throwDOMException(NoModificationAllowedError, "The attribute is read-only."); \
+            SVGPropertyTearOffBase::throwReadOnly(exceptionState); \
             return; \
         } \
         mutableValue()->set##ATTRIBUTE(f); \
         commitChange(); \
     }
 
 DEFINE_SETTER(A);
 DEFINE_SETTER(B);
 DEFINE_SETTER(C);
 DEFINE_SETTER(D);
@@ skipping 60 matching lines @@
 
 SVGMatrixTearOff* SVGMatrixTearOff::multiply(SVGMatrixTearOff* other)
 {
     SVGMatrixTearOff* matrix = create(value());
     *matrix->mutableValue() *= other->value();
     return matrix;
 }
 
 SVGMatrixTearOff* SVGMatrixTearOff::inverse(ExceptionState& exceptionState)
 {
-    AffineTransform transform = value().inverse();
-    if (!value().isInvertible())
+    if (!value().isInvertible()) {
         exceptionState.throwDOMException(InvalidStateError, "The matrix is not invertible.");
-
-    return create(transform);
+        return nullptr;
+    }
+    return create(value().inverse());
 }
 
 SVGMatrixTearOff* SVGMatrixTearOff::rotateFromVector(double x, double y, ExceptionState& exceptionState)
 {
-    if (!x || !y)
+    if (!x || !y) {
         exceptionState.throwDOMException(InvalidAccessError, "Arguments cannot be zero.");
-
+        return nullptr;
+    }
     AffineTransform copy = value();
     copy.rotateFromVector(x, y);
     return create(copy);
 }
 
 DEFINE_TRACE_WRAPPERS(SVGMatrixTearOff)
 {
     visitor->traceWrappers(m_contextTransform);
 }
 
 } // namespace blink