Integrate Crashpad UMA

third_party/crashpad/crashpad/handler/handler_main.cc

Index: third_party/crashpad/crashpad/handler/handler_main.cc
diff --git a/third_party/crashpad/crashpad/handler/handler_main.cc b/third_party/crashpad/crashpad/handler/handler_main.cc
index 3240cd38b37d79d6c915560aa41f325702cf00cd..ccade4b6b56336c8403020bfcb0cd2f29c862092 100644
--- a/third_party/crashpad/crashpad/handler/handler_main.cc
+++ b/third_party/crashpad/crashpad/handler/handler_main.cc
@@ -25,8 +25,10 @@
 
 #include "base/auto_reset.h"
 #include "base/files/file_path.h"
+#include "base/files/file_util.h"
 #include "base/files/scoped_file.h"
 #include "base/logging.h"
+#include "base/metrics/persistent_histogram_allocator.h"
 #include "base/scoped_generic.h"
 #include "base/strings/utf_string_conversions.h"
 #include "build/build_config.h"
@@ -118,6 +120,47 @@ void HandleSIGTERM(int sig, siginfo_t* siginfo, void* context) {
 
 #endif  // OS_MACOSX
 
+// This is used as both the file name and the "allocator" name, which is an
+// internal histograms concept.
+const char kMetricsName[] = "CrashpadMetrics";
+const base::FilePath::CharType kMetricsFileExtension[] =
+    FILE_PATH_LITERAL(".pma");
+
+void InitializePersistentMetricsStorage(const char* database_dir) {
+  const base::FilePath dir(
+      ToolSupport::CommandLineArgumentToFilePathStringType(database_dir));
+
+  // Metrics maps one file that we're going to use during this run (the
+  // "-active" one), and provides the previous one to the metrics system for for
+  // association with the previous run. On startup, we move the current -active
+  // to the base name, and then start this session on the -active one. Normally,
+  // when the browser starts it will read and delete the base name one, but in
+  // the case that something goes wrong, we will overwrite/delete any old one.
+  base::FilePath metrics_file =
+      dir.AppendASCII(kMetricsName).AddExtension(kMetricsFileExtension);
+  base::FilePath active_file =
+      dir.AppendASCII(kMetricsName + std::string("-active"))
+          .AddExtension(kMetricsFileExtension);
+
+  if (!base::ReplaceFile(active_file, metrics_file, nullptr))
+    base::DeleteFile(metrics_file, /*recursive=*/false);
+
+  const size_t kSize = 1 << 20;
+  base::GlobalHistogramAllocator::CreateWithFile(

[bcwhite, 2016/09/13 14:27:48]

This file needs to be deleted when the browser exits cleanly.

Previous-run metrics increase startup time so we definitely don't want to do it
if there is nothing to report.

[scottmg, 2016/09/13 19:15:32]

Ah, I didn't understand the reporting model. So on a clean exit the -active file
just needs to be deleted, but all the data will have been sent to the server
already, so there's no need to do anything like RegisterSource()?

[bcwhite, 2016/09/13 19:38:24]

The model you've selected is that "CrashpadMetrics" will be sent only once and
that is when the browser _next_ starts up, associating those metrics with the
previous run.  It must be registered for that to happen.

You can simply delete the "-active" file upon clean exit and report nothing.

If there are things to report during the _current_ session, then you can also
register the "-active" file with SOURCE_HISTOGRAMS_ACTIVE_FILE and
ASSOCIATE_CURRENT_RUN.  Metrics from that file will be (efficiently) included
during every reporting cycle.  There will be no duplicated reporting of results
even during the next startup because each file knows what has already been
reported from it.

But you should still delete the "-active" file when you know there is nothing
additional to report.

+      active_file, kSize, 0, kMetricsName);
+
+  // Get the allocator that was just created and report result. Exit if the
+  // allocator could not be created.
+  base::GlobalHistogramAllocator* allocator =
+      base::GlobalHistogramAllocator::Get();
+  if (!allocator)
+    return;
+
+  // Create tracking histograms for the allocator and record storage file.
+  allocator->CreateTrackingHistograms(kMetricsName);
+  allocator->SetPersistentLocation(active_file);
+}
+
 }  // namespace
 
 int HandlerMain(int argc, char* argv[]) {
@@ -313,6 +356,15 @@ int HandlerMain(int argc, char* argv[]) {
     return EXIT_FAILURE;
   }
 
+  std::unique_ptr<CrashReportDatabase> database(CrashReportDatabase::Initialize(

[scottmg, 2016/09/02 19:33:54]

This is moved earlier so that the database directory will be created on the
first run, as the memory mapped file is stored there.

+      base::FilePath(ToolSupport::CommandLineArgumentToFilePathStringType(
+          options.database))));
+  if (!database) {
+    return EXIT_FAILURE;
+  }
+
+  InitializePersistentMetricsStorage(options.database);
+
 #if defined(OS_MACOSX)
   if (options.mach_service.empty()) {
     // Don’t do this when being run by launchd. See launchd.plist(5).
@@ -386,13 +438,6 @@ int HandlerMain(int argc, char* argv[]) {
   }
 #endif  // OS_MACOSX
 
-  std::unique_ptr<CrashReportDatabase> database(CrashReportDatabase::Initialize(
-      base::FilePath(ToolSupport::CommandLineArgumentToFilePathStringType(
-          options.database))));
-  if (!database) {
-    return EXIT_FAILURE;
-  }
-
   // TODO(scottmg): options.rate_limit should be removed when we have a
   // configurable database setting to control upload limiting.
   // See https://crashpad.chromium.org/bug/23.