Sandbox the component updater's patcher utility process.

chrome/utility/chrome_content_utility_client.cc

Index: chrome/utility/chrome_content_utility_client.cc
diff --git a/chrome/utility/chrome_content_utility_client.cc b/chrome/utility/chrome_content_utility_client.cc
index b30f9f4661ca176184a3f719c365207ca263557a..69d3006b4d354ff6308335cbd3ba2c0351124a3b 100644
--- a/chrome/utility/chrome_content_utility_client.cc
+++ b/chrome/utility/chrome_content_utility_client.cc
@@ -268,33 +268,26 @@ void ChromeContentUtilityClient::OnCreateZipFile(
 #endif  // defined(OS_CHROMEOS)
 
 void ChromeContentUtilityClient::OnPatchFileBsdiff(
-    const base::FilePath& input_file,
-    const base::FilePath& patch_file,
-    const base::FilePath& output_file) {
-  if (input_file.empty() || patch_file.empty() || output_file.empty()) {

[Noel Gordon, 2016/12/13 05:42:08]

The empty file path detection code was removed here, and I do not see it in
component_patcher_operation_out_of_process.cc. 

So it seems we completely removed the empty path check.  How come? (The change
description for this patch doesn't say).

[waffles, 2016/12/13 17:38:28]

It doesn't make sense to check it here, because we're receiving a file handle,
not a path. We could do some defensive code in
component_patcher_operation_out_of_process to verify it isn't called with empty
paths.

Is this causing a problem?

-    Send(new ChromeUtilityHostMsg_PatchFile_Finished(-1));
-  } else {
-    const int patch_status = bsdiff::ApplyBinaryPatch(input_file,
-                                                      patch_file,
-                                                      output_file);
-    Send(new ChromeUtilityHostMsg_PatchFile_Finished(patch_status));
-  }
+    const IPC::PlatformFileForTransit& input_file,
+    const IPC::PlatformFileForTransit& patch_file,
+    const IPC::PlatformFileForTransit& output_file) {
+  const int patch_status = bsdiff::ApplyBinaryPatch(
+      IPC::PlatformFileForTransitToFile(input_file),
+      IPC::PlatformFileForTransitToFile(patch_file),
+      IPC::PlatformFileForTransitToFile(output_file));
+  Send(new ChromeUtilityHostMsg_PatchFile_Finished(patch_status));
   ReleaseProcessIfNeeded();
 }
 
 void ChromeContentUtilityClient::OnPatchFileCourgette(
-    const base::FilePath& input_file,
-    const base::FilePath& patch_file,
-    const base::FilePath& output_file) {
-  if (input_file.empty() || patch_file.empty() || output_file.empty()) {
-    Send(new ChromeUtilityHostMsg_PatchFile_Finished(-1));
-  } else {
-    const int patch_status = courgette::ApplyEnsemblePatch(
-        input_file.value().c_str(),
-        patch_file.value().c_str(),
-        output_file.value().c_str());
-    Send(new ChromeUtilityHostMsg_PatchFile_Finished(patch_status));
-  }
+    const IPC::PlatformFileForTransit& input_file,
+    const IPC::PlatformFileForTransit& patch_file,
+    const IPC::PlatformFileForTransit& output_file) {
+  const int patch_status = courgette::ApplyEnsemblePatch(
+      IPC::PlatformFileForTransitToFile(input_file),
+      IPC::PlatformFileForTransitToFile(patch_file),
+      IPC::PlatformFileForTransitToFile(output_file));
+  Send(new ChromeUtilityHostMsg_PatchFile_Finished(patch_status));
   ReleaseProcessIfNeeded();
 }