Remove the deprecated static metrics APIs.

src/platform/metrics/README

 Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file.
 
 The Chrome OS "metrics" package contains utilities for client-side
 user metric collection. The collected data is sent to Chrome for
 transport to the UMA server.
 
 
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@@ skipping 24 matching lines @@
 - The API includes two methods:
 
   bool MetricsLibrary::SendToUMA(const std::string& name, int sample,
                                  int min, int max, int nbuckets)
   sends a sample for a regular (exponential) histogram.
 
   bool MetricsLibrary::SendEnumToUMA(const std::string& name, int sample,
                                      int max)
   sends a sample for an enumeration (linear) histogram.
 
-  Currently, the API also includes two deprecated static methods:
-
-  bool MetricsLibrary::SendToChrome(const std::string& name, int sample,
-                                    int min, int max, int nbuckets)
-  bool MetricsLibrary::SendEnumToChrome(const std::string& name, int sample,
-                                        int max)
-
-  See the API documentation in metrics_library.h under
+  Before using these methods, a MetricsLibrary object needs to be
+  constructed and initialized through its Init method. See the
+  complete API documentation in metrics_library.h under
   src/platform/metrics/.
 
 - On the target platform, shortly after the sample is sent it should
   be visible in Chrome through "about:histograms".
 
 
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 Histogram Naming Convention
 ================================================================================
 
@@ skipping 48 matching lines @@
 screen saver states to determine if the user is actively using the
 device or not and generates the corresponding data. The metrics daemon
 uses libmetrics to send the data to Chrome.
 
 The recommended way to generate metrics data from a module is to link
 and use libmetrics directly. However, the module could instead send
 signals to or communicate in some alternative way with the metrics
 daemon. Then the metrics daemon needs to monitor for the relevant
 events and take appropriate action -- for example, aggregate data and
 send the histogram samples.