Fix build with clang on arm where char is unsigned

Upstream-Status: Submitted [https://bugs.webkit.org/show_bug.cgi?id=197087]
Signed-off-by: Khem Raj <raj.khem@gmail.com>

--- a/Source/WebCore/contentextensions/DFACombiner.cpp
+++ b/Source/WebCore/contentextensions/DFACombiner.cpp
@@ -37,7 +37,7 @@ namespace WebCore {
 namespace ContentExtensions {
 
 class DFAMerger {
-    typedef MutableRangeList<char, uint64_t, 128> CombinedTransitionsMutableRangeList;
+    typedef MutableRangeList<signed char, uint64_t, 128> CombinedTransitionsMutableRangeList;
 
     enum class WhichDFA {
         A,
--- a/Source/WebCore/contentextensions/NFAToDFA.cpp
+++ b/Source/WebCore/contentextensions/NFAToDFA.cpp
@@ -41,9 +41,9 @@ namespace WebCore {
 
 namespace ContentExtensions {
 
-typedef MutableRange<char, NFANodeIndexSet> NFANodeRange;
-typedef MutableRangeList<char, NFANodeIndexSet> NFANodeRangeList;
-typedef MutableRangeList<char, NFANodeIndexSet, 128> PreallocatedNFANodeRangeList;
+typedef MutableRange<signed char, NFANodeIndexSet> NFANodeRange;
+typedef MutableRangeList<signed char, NFANodeIndexSet> NFANodeRangeList;
+typedef MutableRangeList<signed char, NFANodeIndexSet, 128> PreallocatedNFANodeRangeList;
 typedef Vector<uint32_t, 0, ContentExtensionsOverflowHandler> UniqueNodeList;
 typedef Vector<UniqueNodeList, 0, ContentExtensionsOverflowHandler> NFANodeClosures;