Pepper: Log in UMA when an interface is used.

ppapi/proxy/interface_list_unittest.cc

Index: ppapi/proxy/interface_list_unittest.cc
diff --git a/ppapi/proxy/interface_list_unittest.cc b/ppapi/proxy/interface_list_unittest.cc
index 17140f06b07fef5260281184897865468e5e5aa0..30557653848edb21fb1edb14efcba561d592e7ed 100644
--- a/ppapi/proxy/interface_list_unittest.cc
+++ b/ppapi/proxy/interface_list_unittest.cc
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "base/hash.h"
 #include "ppapi/c/ppb_core.h"
 #include "ppapi/proxy/interface_list.h"
 #include "ppapi/proxy/ppapi_proxy_test.h"
@@ -62,5 +63,19 @@ TEST_F(InterfaceListTest, DevChannel) {
   ASSERT_TRUE(list.GetInterfaceForPPB(dev_iface_name) == dev_iface_addr);
 }
 
+// Test that the hash function provided by base::Hash is unchanged. This is so
+// that we will generate correct values when logging interface use to UMA.
+TEST_F(InterfaceListTest, InterfaceHash) {
+  std::string name = "PPB_InputEvent;1.0";
+  uint32 data = base::Hash(name.c_str(), name.size());
+  int hash = static_cast<int>(data & 0x7fffffff);

[Alexei Svitkine (slow), 2014/02/04 18:53:31]

Can you make a function in InterfaceList to compute the hash (including the
masking) and call it from this test, rather than duplicating the logic here?
That way, the two won't be able to diverge.

+  EXPECT_EQ(612625164, hash);
+
+  name = "PPB_TCPSocket;1.1";
+  data = base::Hash(name.c_str(), name.size());
+  hash = static_cast<int>(data & 0x7fffffff);
+  EXPECT_EQ(79708274, hash);
+}
+
 }  // namespace proxy
 }  // namespace ppapi