Initial implementation for sharing field trial state (win)

content/browser/child_process_launcher.cc

Index: content/browser/child_process_launcher.cc
diff --git a/content/browser/child_process_launcher.cc b/content/browser/child_process_launcher.cc
index 5a655368aa8bac219446a3ea3586a4c7b6eb7666..f204c0e7ef582a9d1352ddbba5316d5be6a993cf 100644
--- a/content/browser/child_process_launcher.cc
+++ b/content/browser/child_process_launcher.cc
@@ -121,6 +121,7 @@ void LaunchOnLauncherThread(const NotifyCallback& callback,
 #if defined(OS_ANDROID)
                             base::ScopedFD ipcfd,
 #endif
+                            base::SharedMemory* field_trial_state,
                             mojo::edk::ScopedPlatformHandle client_handle,
                             base::CommandLine* cmd_line) {
   DCHECK_CURRENTLY_ON(BrowserThread::PROCESS_LAUNCHER);
@@ -152,9 +153,12 @@ void LaunchOnLauncherThread(const NotifyCallback& callback,
   } else {
     base::HandlesToInheritVector handles;
     handles.push_back(client_handle.get().handle);
+    if (field_trial_state)
+      handles.push_back(field_trial_state->handle().GetHandle());

[Alexei Svitkine (slow), 2016/10/03 15:28:05]

Since both of these functions are const, please pass the parameter to this
function as const as well.

[lawrencewu, 2016/10/03 21:36:11]

Done.

     cmd_line->AppendSwitchASCII(
         mojo::edk::PlatformChannelPair::kMojoPlatformChannelHandleSwitch,
         base::UintToString(base::win::HandleToUint32(handles[0])));
+

[Alexei Svitkine (slow), 2016/10/03 15:28:05]

Nit: Remove extra added line.

[lawrencewu, 2016/10/03 21:36:11]

Done.

     launch_result =
         StartSandboxedProcess(delegate, cmd_line, handles, &process);
   }
@@ -391,6 +395,7 @@ void SetProcessBackgroundedOnLauncherThread(base::Process process,
 
 ChildProcessLauncher::ChildProcessLauncher(
     SandboxedProcessLauncherDelegate* delegate,
+    base::SharedMemory* field_trial_state,

[Alexei Svitkine (slow), 2016/10/03 15:28:05]

Suggest moving this further down - maybe after client? Things like command line
seems to be more important and should be earlier.

[lawrencewu, 2016/10/03 21:36:11]

Done.

     base::CommandLine* cmd_line,
     int child_process_id,
     Client* client,
@@ -414,7 +419,7 @@ ChildProcessLauncher::ChildProcessLauncher(
       weak_factory_(this) {
   DCHECK(CalledOnValidThread());
   CHECK(BrowserThread::GetCurrentThreadIdentifier(&client_thread_id_));
-  Launch(delegate, cmd_line, child_process_id);
+  Launch(delegate, field_trial_state, cmd_line, child_process_id);
 }
 
 ChildProcessLauncher::~ChildProcessLauncher() {
@@ -430,6 +435,7 @@ ChildProcessLauncher::~ChildProcessLauncher() {
 
 void ChildProcessLauncher::Launch(
     SandboxedProcessLauncherDelegate* delegate,
+    base::SharedMemory* field_trial_state,
     base::CommandLine* cmd_line,
     int child_process_id) {
   DCHECK(CalledOnValidThread());
@@ -480,6 +486,7 @@ void ChildProcessLauncher::Launch(
 #if defined(OS_ANDROID)
                  base::Passed(&ipcfd),
 #endif
+                 field_trial_state,
                  base::Passed(&client_handle), cmd_line));
 }