Extended error reporting for SVG attribute parsing

This CL extends the SVG attribute parsing error reporting functionality
to allow more precise (and hopefully helpful) reporting.
The main improvements consist of:

 1) More (precise) status codes
    Avoids generic error messages.

 2) Locus support
    Allows reducing the amount of context, which should make it easier
    to pinpoint the actual error. (Preferably the offending character
    should be highlighted somehow in the error message, but that is
    left as future work.)

To achieve this, the SVGParsingError enumeration is turned into a
thin wrapper class around a status code and a locus. The status codes
move to a new enumeration 'SVGStatus'.

Formatting of error messages are moved out of
SVGElement::reportAttributeParsingError and into SVGParsingError.cpp
(new file).

This CL start adding extended reporting to a few of the value classes:
SVGBoolean, SVGEnumeration and SVGPreserverAspectRatio; to illustrate
the mechanism. Further value classes will be annotated in later CLs.
For that reason the "generic" errors are kept in their current form - to
be removed as more value class parsers get converted.

BUG=231612

Review URL: https://codereview.chromium.org/1588993005

Cr-Commit-Position: refs/heads/master@{#370479}

1 files changed, 1 insertions, 0 deletions

diff --git a/third_party/WebKit/Source/platform/JSONValues.h b/third_party/WebKit/Source/platform/JSONValues.h
index bdb9d2d..44e42c1 100644
--- a/third_party/WebKit/Source/platform/JSONValues.h
+++ b/third_party/WebKit/Source/platform/JSONValues.h
@@ -323,6 +323,7 @@ public:
     using JSONArrayBase::end;
 };
 
+PLATFORM_EXPORT void escapeStringForJSON(const String&, StringBuilder*);
 void doubleQuoteStringForJSON(const String&, StringBuilder*);
 
 } // namespace blink