feat(Compiler): case sensitive html parser

close #4417

Closes #5264

modules/angular2/src/compiler/parse_util.ts

@@ -1,10 +1,8 @@
-import {Math} from 'angular2/src/facade/math';
-
 export class ParseLocation {
   constructor(public file: ParseSourceFile, public offset: number, public line: number,
               public col: number) {}
 
-  toString() { return `${this.file.url}@${this.line}:${this.col}`; }
+  toString(): string { return `${this.file.url}@${this.line}:${this.col}`; }
 }
 
 export class ParseSourceFile {
@@ -16,9 +14,33 @@ export abstract class ParseError {
 
   toString(): string {
     var source = this.location.file.content;
-    var ctxStart = Math.max(this.location.offset - 10, 0);
-    var ctxEnd = Math.min(this.location.offset + 10, source.length);
-    return `${this.msg} (${source.substring(ctxStart, ctxEnd)}): ${this.location}`;
+    var ctxStart = this.location.offset;
+    var ctxEnd = this.location.offset;
+    var ctxLen = 0;
+    var ctxLines = 0;
+
+    while (ctxLen < 100 && ctxStart > 0) {
+      ctxStart--;
+      ctxLen++;
+      if (source[ctxStart] == "\n") {
+        if (++ctxLines == 3) {
+          break;
+        }
+      }
+    }
+
+    ctxLen = 0;
+    ctxLines = 0;
+    while (ctxLen < 100 && ctxEnd < source.length - 1) {
+      ctxEnd++;
+      ctxLen++;
+      if (source[ctxEnd] == "\n") {
+        if (++ctxLines == 3) {
+          break;
+        }
+      }
+    }
+    return `${this.msg} ("${source.substring(ctxStart, ctxEnd + 1)}"): ${this.location}`;
   }
 }