Integrate Crashpad UMA

base/metrics/persistent_histogram_allocator.cc

Index: base/metrics/persistent_histogram_allocator.cc
diff --git a/base/metrics/persistent_histogram_allocator.cc b/base/metrics/persistent_histogram_allocator.cc
index c4d8c95d68da1bf7f36eba9c8538e3d790728486..8bb09cc9055d3d979a68ca36fe708cde38c993b1 100644
--- a/base/metrics/persistent_histogram_allocator.cc
+++ b/base/metrics/persistent_histogram_allocator.cc
@@ -686,7 +686,7 @@ void GlobalHistogramAllocator::CreateWithLocalMemory(
 
 #if !defined(OS_NACL)
 // static
-void GlobalHistogramAllocator::CreateWithFile(
+bool GlobalHistogramAllocator::CreateWithFile(
     const FilePath& file_path,
     size_t size,
     uint64_t id,
@@ -706,14 +706,53 @@ void GlobalHistogramAllocator::CreateWithFile(
   if (!mmfile->IsValid() ||
       !FilePersistentMemoryAllocator::IsFileAcceptable(*mmfile, true)) {
     NOTREACHED();
-    return;
+    return false;
   }
 
   Set(WrapUnique(
       new GlobalHistogramAllocator(MakeUnique<FilePersistentMemoryAllocator>(
           std::move(mmfile), size, id, name, false))));
+  Get()->SetPersistentLocation(file_path);
+  return true;
+}
+
+// static
+bool GlobalHistogramAllocator::CreateWithActiveFile(const FilePath& base_path,
+                                                    const FilePath& active_path,
+                                                    size_t size,
+                                                    uint64_t id,
+                                                    StringPiece name) {
+  if (!base::ReplaceFile(active_path, base_path, nullptr))
+    base::DeleteFile(base_path, /*recursive=*/false);
+
+  return base::GlobalHistogramAllocator::CreateWithFile(active_path, size, id,
+                                                        name);
 }
-#endif
+
+// static
+bool GlobalHistogramAllocator::CreateWithActiveFileInDir(const FilePath& dir,
+                                                         size_t size,
+                                                         uint64_t id,
+                                                         StringPiece name) {
+  FilePath base_path, active_path;
+  ConstructFilePaths(dir, name, &base_path, &active_path);
+  return CreateWithActiveFile(base_path, active_path, size, id, name);
+}
+
+// static
+void GlobalHistogramAllocator::ConstructFilePaths(const FilePath& dir,
+                                                  StringPiece name,
+                                                  FilePath* out_base_path,
+                                                  FilePath* out_active_path) {
+  *out_base_path = dir.AppendASCII(name)

[Alexei Svitkine (slow), 2016/09/15 16:49:44]

Nit: I'd prefer to wrap after the =

But you can keep as-is if this is what git cl format produced.

[scottmg, 2016/09/15 17:41:13]

Yeah, this is clang-format output. It doesn't quite fit only after the =, so one
of the .s has to be a break point anyway.

+                       .AddExtension(PersistentMemoryAllocator::kFileExtension);
+  if (out_active_path) {
+    *out_active_path =
+        dir.AppendASCII(name.as_string() + std::string("-active"))
+            .AddExtension(PersistentMemoryAllocator::kFileExtension);
+  }
+}
+#endif  // !OS_NACL

[Alexei Svitkine (slow), 2016/09/15 16:49:44]

Nit: !defined(OS_NACL)

[scottmg, 2016/09/15 17:41:13]

Done.

 
 // static
 void GlobalHistogramAllocator::CreateWithSharedMemory(
@@ -837,6 +876,18 @@ bool GlobalHistogramAllocator::WriteToPersistentLocation() {
 #endif
 }
 
+void GlobalHistogramAllocator::DeletePersistentLocation() {
+  if (persistent_location_.empty())
+    return;
+
+  // Open (with delete) and then immediately close the file by going out of
+  // scope. This is the only cross-platform safe way to delete a file that may
+  // be open elsewhere. Open handles will continue to operate normally but
+  // new opens will not be possible.
+  File file(persistent_location_,

[Alexei Svitkine (slow), 2016/09/15 16:49:44]

Is this supported for NACL builds? Seems like it shouldn't given the other file
manipulation code isn't.

Maybe we should add a persistent_metrics_file_utils.cc file and move all the
file handled code there instead of having the NACL ifdefs?

[bcwhite, 2016/09/15 17:07:48]

Heh.  I told him to move it in here along-side WriteToPersistentLocation().

Back when working on profiles, there was a general desire *against* _util files
preferring integration or complete segregation.

[scottmg, 2016/09/15 17:41:13]

#ifdef'd for now to match and fix the build. As Brian said I had a
persistent_metrics_file_util.cc/h in a previous CL, but I think this is tidier
overall.

Maybe we could break it up into NaCl files and non-NaCl files in a future change
maybe?

[Alexei Svitkine (slow), 2016/09/15 17:49:16]

Sure, I'm ok with that being explored in a separate CL.

[bcwhite, 2016/09/15 17:56:33]

If I remember correctly, it's only the .cc file that is the problem; I included
the #ifdef in the .h file for correctness-sake.  But you could omit the #ifdef
here and have a separate persistent_histogram_allocator_nonacl.cc file with
those definitions (in that future CL).

+            File::FLAG_OPEN | File::FLAG_READ | File::FLAG_DELETE_ON_CLOSE);
+}
+
 GlobalHistogramAllocator::GlobalHistogramAllocator(
     std::unique_ptr<PersistentMemoryAllocator> memory)
     : PersistentHistogramAllocator(std::move(memory)),