Use RE2/J instead of JsRegExp in JsfileParser.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=260039477

README.md

@@ -378,6 +378,35 @@ an encoding of structured data.</td>
   </tr>
 </table>
 
+### RE2/J
+
+<table>
+  <tr>
+    <td>URL</td>
+    <td>https://github.com/google/re2j</td>
+  </tr>
+
+  <tr>
+    <td>Version</td>
+    <td>1.3</td>
+  </tr>
+
+  <tr>
+    <td>License</td>
+    <td>New BSD License</td>
+  </tr>
+
+  <tr>
+    <td>Description</td>
+    <td>Linear time regular expression matching in Java.</td>
+  </tr>
+
+  <tr>
+    <td>Local Modifications</td>
+    <td>None</td>
+  </tr>
+</table>
+
 ### Truth
 
 <table>

pom-gwt.xml

@@ -166,6 +166,13 @@
       <artifactId>elemental2-core</artifactId>
       <version>1.0.0-beta-1</version>
     </dependency>
+
+    <dependency>
+      <groupId>com.google.re2j</groupId>
+      <artifactId>re2j</artifactId>
+      <version>1.3</version>
+      <classifier>sources</classifier>
+    </dependency>
   </dependencies>
 
   <build>

src/com/google/JsComp.gwt.xml

@@ -19,6 +19,7 @@
   <inherits name="com.google.common.escape.Escape"/>
   <inherits name="com.google.common.io.Io"/>
   <inherits name="com.google.gwt.json.JSON"/>
+  <inherits name="com.google.re2j.RE2J"/>
   <inherits name="elemental2.core.Core"/>
   <source path="debugging/sourcemap"/>
   <source path="javascript/jscomp" excludes=".svn,.git,**/ant/**,**/refactoring/**,**/webservice/**,**/testing/**,**/transpile/**,**/linker/**,**/j2cl/**"/>

src/com/google/javascript/jscomp/gwt/client/JsfileParser.java

@@ -34,7 +34,6 @@
 import com.google.javascript.jscomp.deps.ModuleLoader.ResolutionMode;
 import com.google.javascript.jscomp.gwt.client.Util.JsArray;
 import com.google.javascript.jscomp.gwt.client.Util.JsObject;
-import com.google.javascript.jscomp.gwt.client.Util.JsRegExp;
 import com.google.javascript.jscomp.modules.ModuleMetadataMap.ModuleMetadata;
 import com.google.javascript.jscomp.parsing.Config;
 import com.google.javascript.jscomp.parsing.ParserRunner;
@@ -43,6 +42,8 @@
 import com.google.javascript.rhino.InputId;
 import com.google.javascript.rhino.Node;
 import com.google.javascript.rhino.Token;
+import com.google.re2j.Matcher;
+import com.google.re2j.Pattern;
 import java.util.ArrayList;
 import java.util.LinkedHashSet;
 import java.util.List;
@@ -184,23 +185,21 @@ static List<CommentAnnotation> parse(String comment) {
       //   2. Support custom annotations (may already be done?)
       //   3. Fix up existing code so that all these annotations are in @fileoverview
       //   4. Change this code to simply inspect the script's JSDocInfo instead of re-parsing
-      JsRegExp re = new JsRegExp(
-          ANNOTATION_RE,
-          "g");
-      JsRegExp.Match match;
       List<CommentAnnotation> out = new ArrayList<>();
-      while ((match = re.exec(comment)) != null) {
-        String name = match.get(ANNOTATION_NAME_GROUP);
-        String value = Strings.nullToEmpty(match.get(ANNOTATION_VALUE_GROUP));
+      Matcher matcher = ANNOTATION_RE.matcher(comment);
+      while (matcher.find()) {
+        String name = matcher.group(ANNOTATION_NAME_GROUP);
+        String value = Strings.nullToEmpty(matcher.group(ANNOTATION_VALUE_GROUP));
         out.add(new CommentAnnotation(name, value));
       }
       return out;
     }
 
     // Regex for a JSDoc annotation with an `@name` and an optional brace-delimited `{value}`.
     // The `@` should not match the middle of a word.
-    private static final String ANNOTATION_RE =
-        "(?:[^a-zA-Z0-9_$]|^)(@[a-zA-Z]+)(?:\\s*\\{\\s*([^}\\t\\n\\v\\f\\r ]+)\\s*\\})?";
+    private static final Pattern ANNOTATION_RE =
+        Pattern.compile(
+            "(?:[^a-zA-Z0-9_$]|^)(@[a-zA-Z]+)(?:\\s*\\{\\s*([^}\\t\\n\\v\\f\\r ]+)\\s*\\})?");
     private static final int ANNOTATION_NAME_GROUP = 1;
     private static final int ANNOTATION_VALUE_GROUP = 2;
   }