Start transition the metrics library to non-static API. Use gmock in tests.

src/platform/metrics/metrics_library.cc

Index: src/platform/metrics/metrics_library.cc
diff --git a/src/platform/metrics/metrics_library.cc b/src/platform/metrics/metrics_library.cc
index 95e78b2275b39515b8f54ef493296098d4af8c6d..2accb1ae830ecbb7ad0b5a73ec9e273c4d170c2a 100644
--- a/src/platform/metrics/metrics_library.cc
+++ b/src/platform/metrics/metrics_library.cc
@@ -121,6 +121,9 @@ static int32_t FormatChromeMessage(int32_t buffer_size, char *buffer,
   return message_length;
 }
 
+void MetricsLibrary::Init() {
+}
+
 // static
 bool MetricsLibrary::SendToAutotest(const string& name, int value) {
   FILE *autotest_file = fopen(kAutotestPath, "a+");
@@ -151,6 +154,11 @@ bool MetricsLibrary::SendToChrome(const string& name, int sample,
   return SendMessageToChrome(message_length, message);
 }
 
+bool MetricsLibrary::SendToUMA(const string& name, int sample,
+                               int min, int max, int nbuckets) {
+  return SendToChrome(name, sample, min, max, nbuckets);
+}
+
 //static
 bool MetricsLibrary::SendEnumToChrome(const std::string& name, int sample,
                                       int max) {
@@ -167,3 +175,8 @@ bool MetricsLibrary::SendEnumToChrome(const std::string& name, int sample,
   // Send the message.
   return SendMessageToChrome(message_length, message);
 }
+
+bool MetricsLibrary::SendEnumToUMA(const std::string& name, int sample,
+                                   int max) {
+  return SendEnumToChrome(name, sample, max);
+}