Add weekly crash counters, refactor metrics_daemon, respect opt-in in library.

metrics_library.h

 // 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.
 
 #ifndef METRICS_LIBRARY_H_
 #define METRICS_LIBRARY_H_
 
 #include <sys/types.h>
 #include <string>
 
 #include <gtest/gtest_prod.h>  // for FRIEND_TEST
 
 class MetricsLibraryInterface {
  public:
   virtual void Init() = 0;
   virtual bool SendToUMA(const std::string& name, int sample,
                          int min, int max, int nbuckets) = 0;
   virtual bool SendEnumToUMA(const std::string& name, int sample, int max) = 0;
   virtual ~MetricsLibraryInterface() {}
 };
 
 // Library used to send metrics to both Autotest and Chrome/UMA.
 class MetricsLibrary : public MetricsLibraryInterface {
  public:
   MetricsLibrary();
 
   // Initializes the library.
   void Init();
 
+  // Returns whether or not metrics collection is enabled.
+  bool AreMetricsEnabled();
+
   // Sends histogram data to Chrome for transport to UMA and returns
   // true on success. This method results in the equivalent of an
   // asynchronous non-blocking RPC to UMA_HISTOGRAM_CUSTOM_COUNTS
   // inside Chrome (see base/histogram.h).
   //
   // |sample| is the sample value to be recorded (|min| <= |sample| < |max|).
   // |min| is the minimum value of the histogram samples (|min| > 0).
   // |max| is the maximum value of the histogram samples.
   // |nbuckets| is the number of histogram buckets.
   // [0,min) is the implicit underflow bucket.
@@ skipping 22 matching lines @@
   // is strongly recommended to keep this number low (e.g., 50 is
   // normal, while 100 is high).
   bool SendEnumToUMA(const std::string& name, int sample, int max);
 
   // Sends to Autotest and returns true on success.
   static bool SendToAutotest(const std::string& name, int value);
 
  private:
   friend class CMetricsLibraryTest;
   friend class MetricsLibraryTest;
+  FRIEND_TEST(MetricsLibraryTest, AreMetricsEnabled);
   FRIEND_TEST(MetricsLibraryTest, FormatChromeMessage);
   FRIEND_TEST(MetricsLibraryTest, FormatChromeMessageTooLong);
   FRIEND_TEST(MetricsLibraryTest, SendMessageToChrome);
   FRIEND_TEST(MetricsLibraryTest, SendMessageToChromeUMAEventsBadFileLocation);
 
   // Sends message of size |length| to Chrome for transport to UMA and
   // returns true on success.
   bool SendMessageToChrome(int32_t length, const char* message);
 
   // Formats a name/value message for Chrome in |buffer| and returns the
   // length of the message or a negative value on error.
   //
   // Message format is: | LENGTH(binary) | NAME | \0 | VALUE | \0 |
   //
   // The arbitrary |format| argument covers the non-LENGTH portion of the
   // message. The caller is responsible to store the \0 character
   // between NAME and VALUE (e.g. "%s%c%d", name, '\0', value).
   int32_t FormatChromeMessage(int32_t buffer_size, char* buffer,
                               const char* format, ...);
 
+  // Time at which we last checked if metrics were enabled.
+  static time_t cached_enabled_time_;
+
+  // Cached state of whether or not metrics were enabled.
+  static bool cached_enabled_;
+
   const char* uma_events_file_;
+  const char* consent_file_;
 };
 
 #endif  // METRICS_LIBRARY_H_