Fix some Polymer + Closure typechecking bugs

 * fix compiler assuming return type of "undefined" for behavior methods w/o JSDoc
 * copy "readOnly" behavior properties into .i.js, as the PolymerPass will then generate a setter method for them.

PiperOrigin-RevId: 623516886

Author: lauraharker

src/com/google/javascript/jscomp/PolymerClassRewriter.java

@@ -928,6 +928,13 @@ private void appendBehaviorMembersToBlock(final PolymerClassDefinition cls, Node
             makeParamSafe(param, paramIndex++);
             param = next;
           }
+          if (behaviorFunction.info == null || behaviorFunction.info.getReturnType() == null) {
+            // Record a return type of ? to avoid the type inferencer assuming this function returns
+            // 'undefined' just because it's a stub.
+            info.recordReturnType(
+                new JSTypeExpression(
+                    new Node(Token.QMARK).srcref(fnValue), fnValue.getSourceFileName()));
+          }
         }
 
         exprResult.getFirstChild().setJSDocInfo(info.build());

src/com/google/javascript/jscomp/ijs/PotentialDeclaration.java

@@ -499,7 +499,8 @@ Node getRemovableNode() {
    *     foo: String,
    *     bar: {
    *       type: Number,
-   *       value: 123
+   *       value: 123,
+   *       readOnly: true
    *     }
    *   },
    *   baz: function() {}
@@ -530,13 +531,13 @@ void simplify(AbstractCompiler compiler) {
           propKey = propKey.getNext()) {
         Node propDef = propKey.getOnlyChild();
         // A property definition is either a function reference (e.g. String, Number), or another
-        // object literal. If it's an object literal, only the "type" sub-property matters for type
-        // checking, so we can delete everything else (which may include e.g. a "value" sub-property
-        // with a function expression).
+        // object literal. If it's an object literal, only the "type" and "readOnly" sub-properties
+        // matters for type checking, so we can delete everything else (which may include e.g. a
+        // "value" sub-property with a function expression).
         if (propDef.isObjectLit()) {
           for (Node subProp = propDef.getFirstChild(); subProp != null; ) {
             final Node next = subProp.getNext();
-            if (!subProp.getString().equals("type")) {
+            if (!subProp.getString().equals("type") && !subProp.getString().equals("readOnly")) {
               NodeUtil.deleteNode(subProp, compiler);
             }
             subProp = next;

test/com/google/javascript/jscomp/PolymerPassTest.java

@@ -1774,7 +1774,10 @@ public void testArrowFunctionDefinitionInIifeBehavior() {
                 " * @implements {Polymeres6_TestInterface0} ",
                 " */",
                 "es6.Test = function() {};",
-                "/** @suppress {unusedPrivateMembers} */",
+                "/**",
+                " * @suppress {unusedPrivateMembers}",
+                " * @return {?}",
+                " */",
                 "es6.Test.prototype.sayHi = () => void 0;",
                 "",
                 "es6.Test = Polymer(/** @lends {es6.Test.prototype} */ {",
@@ -3408,6 +3411,7 @@ public void testBehaviorInIIFE() {
             "/**",
             " * @param {string} funAmount",
             " * @suppress {unusedPrivateMembers}",
+            " * @return {?}",
             " */",
             "A.prototype.doSomethingFun = function(funAmount) {};",
             "/** @type {string} */",
@@ -3574,16 +3578,19 @@ public void testBehaviorInModule() {
                 "/**",
                 " * @param {string} funAmount",
                 " * @suppress {unusedPrivateMembers}",
+                " * @return {?}",
                 " */",
                 "A.prototype.doSomethingFun = function(funAmount) {};",
                 "/**",
                 " * @suppress {unusedPrivateMembers}",
+                " * @return {?}",
                 " */",
                 "A.prototype.doSomethingVeryFun =",
                 "    function(a, param$polymer$1, c, veryFun = void 0) {};",
                 "/**",
                 " * @param {string} coolAmount",
                 " * @suppress {unusedPrivateMembers}",
+                " * @return {?}",
                 " */",
                 "A.prototype.doSomethingCool = function(coolAmount) {};",
                 "A = Polymer(/** @lends {A.prototype} */ {",
@@ -3647,7 +3654,10 @@ public void testBehaviorInModule_destructuringRestParams() {
                 "/** @constructor @extends {PolymerElement} @implements {PolymerAInterface0}*/",
                 "var A = function() {};",
                 "/** @type {string} */ A.prototype.name;",
-                "/** @suppress {unusedPrivateMembers} */",
+                "/**",
+                " * @suppress {unusedPrivateMembers}",
+                " * @return {?}",
+                " */",
                 "A.prototype.doSomethingCool =",
                 "    function(param$polymer$0 = void 0, ...param$polymer$1) {};",
                 "A = Polymer(/** @lends {A.prototype} */ {",

test/com/google/javascript/jscomp/ijs/ConvertToTypedInterfaceTest.java

@@ -2325,7 +2325,8 @@ public void testPolymerBehavior() {
             "        return \"foo\";",
             "      },",
             "      reflectToAttribute: true,",
-            "      observer: \"bazChanged\"",
+            "      observer: \"bazChanged\",",
+            "      readOnly: true",
             "    }",
             "  },",
             "  observers: [",
@@ -2365,8 +2366,10 @@ public void testPolymerBehavior() {
             "    bar: Number,",
             "    /** @type {string|number} */",
             "    baz: {",
-            // If the property definition is an object, only the "type" sub-property matters.
-            "      type: String",
+            // If the property definition is an object, only the "type" and "readOnly"
+            // sub-properties matter.
+            "      type: String,",
+            "      readOnly: true",
             "    }",
             "  },",
             // The "observers" configuration doesn't matter.