Reland r8235 "Switch gm to use SkFlags."

tools/SkFlags.cpp

Index: tools/SkFlags.cpp
diff --git a/tools/SkFlags.cpp b/tools/SkFlags.cpp
index b4337d127312c83af90f2fecda5e441833f74698..e386b429fe5ca5dd5e2bb6e38d9401a3c841d6f2 100644
--- a/tools/SkFlags.cpp
+++ b/tools/SkFlags.cpp
@@ -38,8 +38,12 @@ void SkFlags::ParseCommandLine(int argc, char** argv) {
             SkDebugf("Flags:\n");
             SkFlagInfo* flag = SkFlags::gHead;
             while (flag != NULL) {
-                SkDebugf("\t--%s:\ttype: %s\tdefault: %s\n", flag->name().c_str(),
-                          flag->typeAsString().c_str(), flag->defaultValue().c_str());
+                SkDebugf("\t--%s:\ttype: %s", flag->name().c_str(),
+                          flag->typeAsString().c_str());
+                if (flag->defaultValue().size() > 0) {
+                    SkDebugf("\tdefault: %s", flag->defaultValue().c_str());
+                }
+                SkDebugf("\n");
                 const SkString& help = flag->help();
                 size_t length = help.size();
                 const char* currLine = help.c_str();