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

ppapi/tests/test_image_data.cc

Index: ppapi/tests/test_image_data.cc
diff --git a/ppapi/tests/test_image_data.cc b/ppapi/tests/test_image_data.cc
index ed130cdfe2dee5419c3c1972b5665e0ec099a2d1..cd56a52d3dac14a8249d978fc82cd1440a17622a 100644
--- a/ppapi/tests/test_image_data.cc
+++ b/ppapi/tests/test_image_data.cc
@@ -18,7 +18,7 @@ bool TestImageData::Init() {
   return !!image_data_interface_;
 }
 
-void TestImageData::RunTest() {
+void TestImageData::RunTests(const std::string& filter) {
   instance_->LogTest("InvalidFormat", TestInvalidFormat());
   instance_->LogTest("InvalidSize", TestInvalidSize());
   instance_->LogTest("HugeSize", TestHugeSize());