Report hash of Chrome's parent process name.

chrome/browser/install_verification/win/install_verification.cc

Index: chrome/browser/install_verification/win/install_verification.cc
diff --git a/chrome/browser/install_verification/win/install_verification.cc b/chrome/browser/install_verification/win/install_verification.cc
index 82c1d8180b301e33ea854812ed53a37ea03c234b..4de7bd623666317818093dd79903b584d7256bbc 100644
--- a/chrome/browser/install_verification/win/install_verification.cc
+++ b/chrome/browser/install_verification/win/install_verification.cc
@@ -5,15 +5,21 @@
 #include "chrome/browser/install_verification/win/install_verification.h"
 
 #include <stddef.h>
+#include <windows.h>
 
 #include <set>
 #include <vector>
 
+#include "base/files/file_path.h"
 #include "base/metrics/sparse_histogram.h"
+#include "base/process/process.h"
+#include "base/process/process_handle.h"
+#include "base/strings/string_util.h"
 #include "chrome/browser/install_verification/win/loaded_module_verification.h"
 #include "chrome/browser/install_verification/win/module_ids.h"
 #include "chrome/browser/install_verification/win/module_info.h"
 #include "chrome/browser/install_verification/win/module_verification_common.h"
+#include "components/variations/metrics_util.h"
 
 namespace {
 
@@ -21,9 +27,51 @@ void ReportModuleMatch(size_t module_id) {
   UMA_HISTOGRAM_SPARSE_SLOWLY("InstallVerifier.ModuleMatch", module_id);
 }
 
+base::FilePath GetExeFilePathForProcess(const base::Process& process) {
+  wchar_t exe_name[MAX_PATH];
+  DWORD exe_name_len = arraysize(exe_name);
+  // Note: requesting the Win32 path format.
+  if (::QueryFullProcessImageName(process.Handle(), 0, exe_name,
+                                  &exe_name_len) == 0) {
+    DPLOG(ERROR) << "Failed to get executable name for process";
+    return base::FilePath();
+  }
+
+  // QueryFullProcessImageName's documentation does not specify behavior when
+  // the buffer is too small, but we know that GetModuleFileNameEx succeeds and
+  // truncates the returned name in such a case. Given that paths of arbitrary
+  // length may exist, the conservative approach is to reject names when
+  // the returned length is that of the buffer.
+  if (exe_name_len > 0 && exe_name_len < arraysize(exe_name))
+    return base::FilePath(exe_name);
+
+  return base::FilePath();
+}
+
+void ReportParentProcessName() {
+  base::ProcessId ppid =
+      base::GetParentProcessId(base::GetCurrentProcessHandle());
+
+  base::Process process(
+      base::Process::OpenWithAccess(ppid, PROCESS_QUERY_LIMITED_INFORMATION));
+
+  uint32_t hash = 0U;
+
+  if (process.IsValid()) {
+    base::FilePath path(GetExeFilePathForProcess(process));
+
+    if (!path.empty())

[robertshield, 2016/06/09 03:29:59]

nit: I thought we needed {} if the statement below spans multiple lines. Ignore
this comment if git cl format suggested this. 

[Will Harris, 2016/06/09 03:35:47]

git cl format never adds braces even when they are needed...

In this case you're right and I'll add them.

[Will Harris, 2016/06/09 16:22:51]

Done.

+      hash =
+          metrics::HashName(base::ToLowerASCII(path.BaseName().AsUTF8Unsafe()));

[Alexei Svitkine (slow), 2016/06/09 15:04:26]

Nit: AsUTF8Unsafe() stands out and makes the reader question if this is correct.

How about just using UTF16ToUTF8() on .value() - since on Windows Filepath uses
string16 as the value type.

[Will Harris, 2016/06/09 16:22:51]

Done.

+  }
+
+  UMA_HISTOGRAM_SPARSE_SLOWLY("Windows.ParentProcessNameHash", hash);
+}
+
 }  // namespace
 
 void VerifyInstallation() {
+  ReportParentProcessName();
   ModuleIDs module_ids;
   LoadModuleIDs(&module_ids);
   std::set<ModuleInfo> loaded_modules;