Move char codes from high surrogate pair range into private use.

Fixes #2884

src/core/fonts.js

@@ -467,6 +467,8 @@ var ProblematicCharRanges = new Int32Array([
   0x3164, 0x3165,
   // Chars that is used in complex-script shaping.
   0xAA60, 0xAA80,
+  // Unicode high surrogates.
+  0xD800, 0xE000,
   // Specials Unicode block.
   0xFFF0, 0x10000
 ]);

test/pdfs/.gitignore

@@ -216,6 +216,7 @@
 !bug1175962.pdf
 !bug1020226.pdf
 !basicapi.pdf
+!issue2884_reduced.pdf
 !mixedfonts.pdf
 !shading_extend.pdf
 !noembed-identity.pdf

test/test_manifest.json

@@ -1317,6 +1317,14 @@
        "lastPage": 1,
        "type": "eq"
     },
+    {  "id": "issue2884_reduced",
+       "file": "pdfs/issue2884_reduced.pdf",
+       "md5": "18386542fc82affa2a5d3722549f8211",
+       "rounds": 1,
+       "link": false,
+       "lastPage": 1,
+       "type": "eq"
+    },
     {  "id": "bug956965",
        "file": "pdfs/bug956965.pdf",
        "md5": "9b2f1176c797ee84e989a507e745f89d",

test/unit/fonts_spec.js

@@ -83,7 +83,7 @@ var checkProblematicCharRanges = function checkProblematicCharRanges() {
 
 describe('Fonts', function() {
   it('checkProblematicCharRanges', function() {
-    var EXPECTED_PERCENTAGE = 45;
+    var EXPECTED_PERCENTAGE = 100;
     var result = checkProblematicCharRanges();
 
     expect(result.percentage).toBeLessThan(EXPECTED_PERCENTAGE);