Adding support for controlling the global sRGB SkColor switch.

tools/skiaserve/urlhandlers/UrlHandler.h

Index: tools/skiaserve/urlhandlers/UrlHandler.h
diff --git a/tools/skiaserve/urlhandlers/UrlHandler.h b/tools/skiaserve/urlhandlers/UrlHandler.h
index adbdcb9aa2e3540eb3ecc06b9c4f2fef5a9eadc5..d767aaebd4eb6a1fee7d65c4473a41cb644fa868 100644
--- a/tools/skiaserve/urlhandlers/UrlHandler.h
+++ b/tools/skiaserve/urlhandlers/UrlHandler.h
@@ -141,3 +141,16 @@ public:
                const char* url, const char* method,
                const char* upload_data, size_t* upload_data_size) override;
 };
+
+/**
+ * Controls the global sRGB flag (is SkColor treated as sRGB or not).
+ * Posting to /srgbMode/0 causes SkColor to be linear, /colorMode/1
+ * causes SkColor to be sRGB;
+ */
+class SRGBModeHandler : public UrlHandler {
+public:
+    bool canHandle(const char* method, const char* url) override;
+    int handle(Request* request, MHD_Connection* connection,
+               const char* url, const char* method,
+               const char* upload_data, size_t* upload_data_size) override;
+};