Remove the --allow-no-sandbox-job flag in favor of automatic recognition.

content/common/sandbox_win.cc

Index: content/common/sandbox_win.cc
diff --git a/content/common/sandbox_win.cc b/content/common/sandbox_win.cc
index 6dee6e96a96299cd3aa01a46772f727c46ec6bf4..7f2742acf1bfd4fa9c77a71b0f152000ada862e7 100644
--- a/content/common/sandbox_win.cc
+++ b/content/common/sandbox_win.cc
@@ -251,9 +251,6 @@ base::string16 PrependWindowsSessionPath(const base::char16* object) {
 
 // Checks if the sandbox should be let to run without a job object assigned.

[jwd, 2017/03/02 19:58:14]

So, this comment implies to me that a return of true means that the sandbox
should be let to run without a job object assigned. The code, or at least the
use of the kAllowNoSandboxJob makes me think that it's the reverse. If it is the
reverse, can you update this comment to make that clearer?

[pastarmovj, 2017/03/02 20:21:21]

I clarified the return value of the function.

 bool ShouldSetJobLevel(const base::CommandLine& cmd_line) {
-  if (!cmd_line.HasSwitch(switches::kAllowNoSandboxJob))
-    return true;
-
   // Windows 8 allows nested jobs so we don't need to check if we are in other
   // job.
   if (base::win::GetVersion() >= base::win::VERSION_WIN8)
@@ -277,6 +274,25 @@ bool ShouldSetJobLevel(const base::CommandLine& cmd_line) {
   if (job_info.BasicLimitInformation.LimitFlags & JOB_OBJECT_LIMIT_BREAKAWAY_OK)
     return true;
 
+  // Lastly in place of the flag which was supposed to be used only for running
+  // Chrome in remote sessions we do this check explicitly here.
+  // According to MS this flag can be false for a remote session only on Windows
+  // Server 2012 and newer so if we do the check last we should be on the safe
+  // side. See: https://msdn.microsoft.com/en-us/library/aa380798.aspx.
+  if (!::GetSystemMetrics(SM_REMOTESESSION)) {
+    // Measure how often we would have decided to apply the sandbox but the
+    // user actually wanted to avoid it.
+    // TODO(pastarmovj): Remove this check and the flag altogether once we are
+    // convinced that the automatic logic is good enough.
+    bool set_job = !cmd_line.HasSwitch(switches::kAllowNoSandboxJob);
+    UMA_HISTOGRAM_BOOLEAN("Process.Sandbox.JobAvoidedCorrectly", set_job);
+    return set_job;
+  }
+
+  // Allow running without the sandbox in this case. This slightly reduces the
+  // ability of the sandbox to protect its children from spawning new processes
+  // or preventing them from shutting down Windows or accessing the clipboard.
+  UMA_HISTOGRAM_BOOLEAN("Process.Sandbox.JobAvoidedCorrectly", true);
   return false;
 }