Issue 5359. Highlight 'on' in try-catch statement.

compiler/java/com/google/dart/compiler/parser/DartParser.java

Index: compiler/java/com/google/dart/compiler/parser/DartParser.java
diff --git a/compiler/java/com/google/dart/compiler/parser/DartParser.java b/compiler/java/com/google/dart/compiler/parser/DartParser.java
index e6104b6a5016fcbc0011096471b38bfc2c6d1435..591c54ac8bf76fc3d5462b1fa0ea15e806606167 100644
--- a/compiler/java/com/google/dart/compiler/parser/DartParser.java
+++ b/compiler/java/com/google/dart/compiler/parser/DartParser.java
@@ -5080,6 +5080,7 @@ public class DartParser extends CompletionHooksParserBase {
       if (peekPseudoKeyword(0, ON_KEYWORD)) {
         beginCatchClause();
         next();
+        int onTokenOffset = position();
         DartTypeNode exceptionType = parseTypeAnnotation();
         DartParameter exception = null;
         DartParameter stackTrace = null;
@@ -5106,7 +5107,7 @@ public class DartParser extends CompletionHooksParserBase {
           setMetadata(exception, metadata);
         }
         DartBlock block = parseBlock();
-        catches.add(done(new DartCatchBlock(block, exception, stackTrace)));
+        catches.add(done(new DartCatchBlock(block, onTokenOffset, exception, stackTrace)));
       } else {
         beginCatchClause();
         next();
@@ -5139,7 +5140,7 @@ public class DartParser extends CompletionHooksParserBase {
         }
         expectCloseParen();
         DartBlock block = parseBlock();
-        catches.add(done(new DartCatchBlock(block, exception, stackTrace)));
+        catches.add(done(new DartCatchBlock(block, -1, exception, stackTrace)));
       }
     }