Make it possible to enable/disable specific ppapi tests. Migrate PostMessage tests.

ppapi/tests/test_uma.cc

Index: ppapi/tests/test_uma.cc
diff --git a/ppapi/tests/test_uma.cc b/ppapi/tests/test_uma.cc
index a310e8f8ba84cc8f8db3d6e3a506abb2fa1a89f5..a780282a879736d8a4b1dd45dfc66e48351ae42b 100644
--- a/ppapi/tests/test_uma.cc
+++ b/ppapi/tests/test_uma.cc
@@ -17,7 +17,7 @@ bool TestUMA::Init() {
   return !!uma_interface_;
 }
 
-void TestUMA::RunTest() {
+void TestUMA::RunTests(const std::string& filter) {
   instance_->LogTest("Count", TestCount());
   instance_->LogTest("Time", TestTime());
   instance_->LogTest("Enum", TestEnum());