Improve core/css exception messages.

Source/core/css/FontFaceSet.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 277 matching lines @@
     DEFINE_STATIC_LOCAL(String, space, (" "));
     return s.isNull() ? space : s;
 }
 
 Vector<RefPtr<FontFace> > FontFaceSet::match(const String& fontString, const String& text, ExceptionState& exceptionState)
 {
     Vector<RefPtr<FontFace> > matchedFonts;
 
     Font font;
     if (!resolveFontStyle(fontString, font)) {
-        exceptionState.throwUninformativeAndGenericDOMException(SyntaxError);
+        exceptionState.throwDOMException(SyntaxError, "Could not resolve '" + fontString + "' as a font.");
         return matchedFonts;
     }
 
     for (const FontFamily* f = &font.family(); f; f = f->next()) {
         CSSSegmentedFontFace* face = document()->styleEngine()->fontSelector()->getFontFace(font.fontDescription(), f->family());
         if (face)
             matchedFonts.append(face->fontFaces(nullToSpace(text)));
     }
     return matchedFonts;
 }
 
 ScriptPromise FontFaceSet::load(const String& fontString, const String& text, ExceptionState& exceptionState)
 {
     Font font;
     if (!resolveFontStyle(fontString, font)) {
-        exceptionState.throwUninformativeAndGenericDOMException(SyntaxError);
+        exceptionState.throwDOMException(SyntaxError, "Could not resolve '" + fontString + "' as a font.");
         return ScriptPromise();
     }
 
     Document* d = document();
     ScriptPromise promise = ScriptPromise::createPending(executionContext());
     RefPtr<LoadFontPromiseResolver> resolver = LoadFontPromiseResolver::create(font.family(), promise, executionContext());
     for (const FontFamily* f = &font.family(); f; f = f->next()) {
         CSSSegmentedFontFace* face = d->styleEngine()->fontSelector()->getFontFace(font.fontDescription(), f->family());
         if (!face) {
             resolver->error();
             continue;
         }
         face->loadFont(font.fontDescription(), nullToSpace(text), resolver);
     }
     return promise;
 }
 
 bool FontFaceSet::check(const String& fontString, const String& text, ExceptionState& exceptionState)
 {
     Font font;
     if (!resolveFontStyle(fontString, font)) {
-        exceptionState.throwUninformativeAndGenericDOMException(SyntaxError);
+        exceptionState.throwDOMException(SyntaxError, "Could not resolve '" + fontString + "' as a font.");
         return false;
     }
 
     for (const FontFamily* f = &font.family(); f; f = f->next()) {
         CSSSegmentedFontFace* face = document()->styleEngine()->fontSelector()->getFontFace(font.fontDescription(), f->family());
         if (!face || !face->checkFont(nullToSpace(text)))
             return false;
     }
     return true;
 }
@@ skipping 69 matching lines @@
 }
 
 void FontFaceSet::didLayout(Document* document)
 {
     if (FontFaceSet* fonts = static_cast<FontFaceSet*>(SupplementType::from(document, supplementName())))
         fonts->didLayout();
 }
 
 
 } // namespace WebCore