Don't throw for unparseable frames.

lib/src/frame.dart

Index: lib/src/frame.dart
diff --git a/lib/src/frame.dart b/lib/src/frame.dart
index a5fd6ae2df0554ceb4a7dba0ce0ef6733db1d9b5..072983a1b3c03ad4a63268fe529fa9eae4e0f267 100644
--- a/lib/src/frame.dart
+++ b/lib/src/frame.dart
@@ -7,6 +7,7 @@ library frame;
 import 'package:path/path.dart' as path;
 
 import 'trace.dart';
+import 'unparsed_frame.dart';
 
 // #1      Foo._bar (file:///home/nweiz/code/stuff.dart:42:21)
 // #1      Foo._bar (file:///home/nweiz/code/stuff.dart:42)
@@ -126,7 +127,7 @@ class Frame {
   }
 
   /// Parses a string representation of a Dart VM stack frame.
-  factory Frame.parseVM(String frame) {
+  factory Frame.parseVM(String frame) => _catchFormatException(frame, () {
     // The VM sometimes folds multiple stack frames together and replaces them
     // with "...".
     if (frame == '...') {
@@ -134,9 +135,7 @@ class Frame {
     }
 
     var match = _vmFrame.firstMatch(frame);
-    if (match == null) {
-      throw new FormatException("Couldn't parse VM stack trace line '$frame'.");
-    }
+    if (match == null) return new UnparsedFrame(frame);
 
     // Get the pieces out of the regexp match. Function, URI and line should
     // always be found. The column is optional.
@@ -149,14 +148,12 @@ class Frame {
     var line = lineAndColumn.length > 1 ? int.parse(lineAndColumn[1]) : null;
     var column = lineAndColumn.length > 2 ? int.parse(lineAndColumn[2]) : null;
     return new Frame(uri, line, column, member);
-  }
+  });
 
   /// Parses a string representation of a Chrome/V8 stack frame.
-  factory Frame.parseV8(String frame) {
+  factory Frame.parseV8(String frame) => _catchFormatException(frame, () {
     var match = _v8Frame.firstMatch(frame);
-    if (match == null) {
-      throw new FormatException("Couldn't parse V8 stack trace line '$frame'.");
-    }
+    if (match == null) return new UnparsedFrame(frame);
 
     // v8 location strings can be arbitrarily-nested, since it adds a layer of
     // nesting for each eval performed on that line.
@@ -172,10 +169,7 @@ class Frame {
       }
 
       var urlMatch = _v8UrlLocation.firstMatch(location);
-      if (urlMatch == null) {
-        throw new FormatException(
-            "Couldn't parse V8 stack trace line '$frame'.");
-      }
+      if (urlMatch == null) return new UnparsedFrame(frame);
 
       return new Frame(
           _uriOrPathToUri(urlMatch[1]),
@@ -197,7 +191,7 @@ class Frame {
       // functions.
       return parseLocation(match[3], "<fn>");
     }
-  }
+  });
 
   /// Parses a string representation of a JavaScriptCore stack trace.
   factory Frame.parseJSCore(String frame) => new Frame.parseV8(frame);
@@ -209,12 +203,9 @@ class Frame {
   factory Frame.parseIE(String frame) => new Frame.parseV8(frame);
 
   /// Parses a string representation of a Firefox stack frame.
-  factory Frame.parseFirefox(String frame) {
+  factory Frame.parseFirefox(String frame) => _catchFormatException(frame, () {
     var match = _firefoxSafariFrame.firstMatch(frame);
-    if (match == null) {
-      throw new FormatException(
-          "Couldn't parse Firefox/Safari stack trace line '$frame'.");
-    }
+    if (match == null) return new UnparsedFrame(frame);
 
     // Normally this is a URI, but in a jsshell trace it can be a path.
     var uri = _uriOrPathToUri(match[3]);
@@ -237,7 +228,7 @@ class Frame {
     var column = match[5] == null || match[5] == '' ?
         null : int.parse(match[5]);
     return new Frame(uri, line, column, member);
-  }
+  });
 
   /// Parses a string representation of a Safari 6.0 stack frame.
   @Deprecated("Use Frame.parseSafari instead.")
@@ -251,7 +242,7 @@ class Frame {
   factory Frame.parseSafari(String frame) => new Frame.parseFirefox(frame);
 
   /// Parses this package's string representation of a stack frame.
-  factory Frame.parseFriendly(String frame) {
+  factory Frame.parseFriendly(String frame) => _catchFormatException(frame, () {
     var match = _friendlyFrame.firstMatch(frame);
     if (match == null) {
       throw new FormatException(
@@ -268,7 +259,7 @@ class Frame {
     var line = match[2] == null ? null : int.parse(match[2]);
     var column = match[3] == null ? null : int.parse(match[3]);
     return new Frame(uri, line, column, match[4]);
-  }
+  });
 
   /// A regular expression matching an absolute URI.
   static final _uriRegExp = new RegExp(r'^[a-zA-Z][-+.a-zA-Z\d]*://');
@@ -294,6 +285,18 @@ class Frame {
     return Uri.parse(uriOrPath);
   }
 
+  /// Runs [body] and returns its result.
+  ///
+  /// If [body] throws a [FormatException], returns an [UnparsedFrame] with
+  /// [text] instead.
+  static Frame _catchFormatException(String text, Frame body()) {
+    try {
+      return body();
+    } on FormatException catch (_) {
+      return new UnparsedFrame(text);
+    }
+  }
+
   Frame(this.uri, this.line, this.column, this.member);
 
   String toString() => '$location in $member';