[sql] Track uploads of diagnostic data to prevent duplication.

components/history/core/browser/thumbnail_database.cc

Index: components/history/core/browser/thumbnail_database.cc
diff --git a/components/history/core/browser/thumbnail_database.cc b/components/history/core/browser/thumbnail_database.cc
index 35afa12319fc9a021b6c7c3d7dfd30971e35cf5f..730e0695d2a56edcb333c933b3c01a169d333fc9 100644
--- a/components/history/core/browser/thumbnail_database.cc
+++ b/components/history/core/browser/thumbnail_database.cc
@@ -254,6 +254,9 @@ void GenerateDiagnostics(sql::Connection* db,
     // Set first in case of errors in generating the report.
     reported = true;
 
+    if (!db->ShouldUploadDiagnosticDump())
+      return;

[pkotwicz, 2015/10/15 18:02:29]

Nit - I think that this is slightly clearer:

if (db->ShouldUploadDiagnosticDump()) {
  // Corrupt cases currently dominate, report them very infrequently.
  const uint64 kCorruptReportsPerMillion = 10000;
  if (rand < kCorruptReportsPerMillion)
    ReportCorrupt(db, startup_kb);
}

[Scott Hess - ex-Googler, 2015/10/15 21:12:20]

OK, I pulled all of these to just before the Report line.  I could push the
check into the Report functions, but I'm thinking the entire ball of wax should
be refactored.  If this change successfully moderates the reporting rate, then
it would make sense to remove much of the special-casing in this function.

+
     // Corrupt cases currently dominate, report them very infrequently.
     static const uint64 kCorruptReportsPerMillion = 10000;
     if (rand < kCorruptReportsPerMillion)
@@ -263,6 +266,9 @@ void GenerateDiagnostics(sql::Connection* db,
     // is seen, it is almost guaranteed to be seen again.
     reported = true;
 
+    if (!db->ShouldUploadDiagnosticDump())
+      return;
+
     if (rand < kReportsPerMillion)
       ReportError(db, extended_error);
   } else {
@@ -276,6 +282,8 @@ void GenerateDiagnostics(sql::Connection* db,
     // channels, so probably easier to just harvest from the field.
     if (rand < kReportsPerMillion) {
       reported = true;
+      if (!db->ShouldUploadDiagnosticDump())
+        return;
       ReportError(db, extended_error);
     }
   }