Add use-chromium-style-naming option to Blink GC plugin.

tools/clang/blink_gc_plugin/tests/traceimpl_error.txt

Index: tools/clang/blink_gc_plugin/tests/traceimpl_error.txt
diff --git a/tools/clang/blink_gc_plugin/tests/traceimpl_error.txt b/tools/clang/blink_gc_plugin/tests/traceimpl_error.txt
index 070b02961c0953d3fc2ba8674ec4e158fa1471a1..ec976a084d1ca2b05b25aa5bf4d2d794f9136e08 100644
--- a/tools/clang/blink_gc_plugin/tests/traceimpl_error.txt
+++ b/tools/clang/blink_gc_plugin/tests/traceimpl_error.txt
@@ -1,20 +1,20 @@
 In file included from traceimpl_error.cpp:5:
 ./traceimpl_error.h:23:3: warning: [blink-gc] Class 'TraceImplInlinedWithUntracedMember' has untraced fields that require tracing.
-  void traceImpl(VisitorDispatcher visitor) {
+  void TraceImpl(VisitorDispatcher visitor) {
   ^
 ./traceimpl_error.h:28:3: note: [blink-gc] Untraced field 'x_' declared here:
   Member<X> x_;
   ^
 ./traceimpl_error.h:53:3: warning: [blink-gc] Base class 'Base' of derived class 'TraceImplInlineWithUntracedBase' requires tracing.
-  void traceImpl(VisitorDispatcher visitor) {
+  void TraceImpl(VisitorDispatcher visitor) {
   ^
 traceimpl_error.cpp:14:1: warning: [blink-gc] Class 'TraceImplExternWithUntracedMember' has untraced fields that require tracing.
-inline void TraceImplExternWithUntracedMember::traceImpl(
+inline void TraceImplExternWithUntracedMember::TraceImpl(
 ^
 ./traceimpl_error.h:40:3: note: [blink-gc] Untraced field 'x_' declared here:
   Member<X> x_;
   ^
 traceimpl_error.cpp:24:1: warning: [blink-gc] Base class 'Base' of derived class 'TraceImplExternWithUntracedBase' requires tracing.
-inline void TraceImplExternWithUntracedBase::traceImpl(
+inline void TraceImplExternWithUntracedBase::TraceImpl(
 ^
 4 warnings generated.