Change the meaning of MobileSessionShutdownType's FIRST_LAUNCH_AFTER_UPGRADE bucket.

ios/chrome/browser/metrics/ios_stability_metrics_provider.h

 // Copyright 2015 The Chromium 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 IOS_CHROME_BROWSER_METRICS_IOS_STABILITY_METRICS_PROVIDER_H_
 #define IOS_CHROME_BROWSER_METRICS_IOS_STABILITY_METRICS_PROVIDER_H_
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "components/metrics/metrics_provider.h"
 
 namespace metrics {
 class MetricsService;
 }
 
 // Exposed for testing purposes only.
 // Values of the UMA Stability.MobileSessionShutdownType histogram.
 enum MobileSessionShutdownType {
   SHUTDOWN_IN_BACKGROUND = 0,
   SHUTDOWN_IN_FOREGROUND_NO_CRASH_LOG_NO_MEMORY_WARNING,
   SHUTDOWN_IN_FOREGROUND_WITH_CRASH_LOG_NO_MEMORY_WARNING,
   SHUTDOWN_IN_FOREGROUND_NO_CRASH_LOG_WITH_MEMORY_WARNING,
   SHUTDOWN_IN_FOREGROUND_WITH_CRASH_LOG_WITH_MEMORY_WARNING,
-  FIRST_LAUNCH_AFTER_UPGRADE,
+  DEPRECATED_FIRST_LAUNCH_AFTER_UPGRADE,
+  SHUTDOWN_IN_FOREGROUND_UNKNOWN_LOG_STATE,

[stuartmorgan, 2015/07/21 20:16:24]

Seems like we should keep the fact that it's post-upgrade; it's a very specific
reason we have an unknown log state.

[stuartmorgan, 2015/07/28 22:27:43]

I still think this is true.

   MOBILE_SESSION_SHUTDOWN_TYPE_COUNT,
 };
 
 class IOSStabilityMetricsProvider : public metrics::MetricsProvider {
  public:
   explicit IOSStabilityMetricsProvider(
       metrics::MetricsService* metrics_service);
   ~IOSStabilityMetricsProvider() override;
 
   // metrics::MetricsProvider
@@ skipping 19 matching lines @@
 
   // Whether there was a memory warning shortly before last shutdown.
   virtual bool ReceivedMemoryWarningBeforeLastShutdown();
 
  private:
   metrics::MetricsService* metrics_service_;
   DISALLOW_COPY_AND_ASSIGN(IOSStabilityMetricsProvider);
 };
 
 #endif  // IOS_CHROME_BROWSER_METRICS_IOS_STABILITY_METRICS_PROVIDER_H_