Revert of Leak reports collect information about the last uptrend

components/metrics/proto/memory_leak_report.proto

 // Copyright 2016 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.
 
 syntax = "proto2";
 
 option optimize_for = LITE_RUNTIME;
 
 package metrics;
 
@@ skipping 91 matching lines @@
   // allocation. The oldest record is at the beginning. The most recent record,
   // taken at the time the report was generated, is at the end.
   repeated AllocationBreakdown alloc_breakdown_history = 4;
 
   // The following two fields describe the last increasing trend in the number
   // of allocations from the size and call stack that generated this
   // leak report.
   //
   // |num_rising_intervals| equals timeslot_now - timeslot_drop,
   // where timeslot_drop is the timeslot number of the last frame that saw
-  // a drop in the number of allocations, or the first frame in the history
-  // if there were no drops (history is cleared when the net number of
-  // allocations hits 0).
+  // a drop in the number of allocations (or 0 if there were no drops).
   // If it is < 32, it will be visible in the allocation history graph.
   // If it is >= 32, it will not be seen in the graph.
   // E.g. for history [3,2,4,4,7] |num_rising_intervals| equals 3.
   optional uint32 num_rising_intervals = 7;
 
   // Indicates the magnitude of the current uptrend in allocations.
   // E.g. for history [3,2,4,4,7] |num_allocs_increase| equals 5.
   optional uint32 num_allocs_increase = 8;
 
   //////////////////////////////////////////////////////////////////////////////
 
   // Contains additional data about the memory usage from the OS.
   // There is no need to store the total system memory as it is
   // available under SystemProfileProto::Hardware::system_ram_mb.
   //
   // Next tag: 3
   message MemoryUsageInfo {
     // How much available physical memory the system has.
     optional uint64 available_ram_mb = 1;
 
     // Total private working set memory across all Chrome processes.
     optional uint64 chrome_ram_usage_mb = 2;
   }
 
   // Information about the memory usage from the OS collected right after
   // the leak report was created in the leak detector.
   optional MemoryUsageInfo memory_usage_info = 9;
 }