Initial implementation for sharing field trial state (win)

content/browser/renderer_host/render_process_host_impl.cc

Index: content/browser/renderer_host/render_process_host_impl.cc
diff --git a/content/browser/renderer_host/render_process_host_impl.cc b/content/browser/renderer_host/render_process_host_impl.cc
index 00f88e99958af2563e24f2a1e09c9d1f1b39263c..c7ebb8d10b89cf150d467318a51c4f5291f2e732 100644
--- a/content/browser/renderer_host/render_process_host_impl.cc
+++ b/content/browser/renderer_host/render_process_host_impl.cc
@@ -967,7 +967,11 @@ bool RenderProcessHostImpl::Init() {
     // As long as there's no renderer prefix, we can use the zygote process
     // at this stage.
     child_process_launcher_.reset(new ChildProcessLauncher(
-        new RendererSandboxedProcessLauncherDelegate(channel_.get()), cmd_line,
+        new RendererSandboxedProcessLauncherDelegate(channel_.get()),
+#if defined(OS_WIN)
+        field_trial_state_.get()->handle().GetHandle(),

[Alexei Svitkine (slow), 2016/09/30 21:47:52]

Can we pass base::SharedMemory* instead of HANDLE? Then, the code doesn't have
to be Windows specific and you can avoid a lot of ifdefs.

[lawrencewu, 2016/10/03 14:14:36]

Done.

+#endif
+        cmd_line,
         GetID(), this, child_token_,
         base::Bind(&RenderProcessHostImpl::OnMojoError,
                    weak_factory_.GetWeakPtr(),
@@ -1587,7 +1591,7 @@ static void AppendCompositorCommandLineFlags(base::CommandLine* command_line) {
 }
 
 void RenderProcessHostImpl::AppendRendererCommandLine(
-    base::CommandLine* command_line) const {
+    base::CommandLine* command_line) {
   // Pass the process type first, so it shows first in process listings.
   command_line->AppendSwitchASCII(switches::kProcessType,
                                   switches::kRendererProcess);
@@ -1626,7 +1630,7 @@ void RenderProcessHostImpl::AppendRendererCommandLine(
 
 void RenderProcessHostImpl::PropagateBrowserCommandLineToRenderer(
     const base::CommandLine& browser_cmd,
-    base::CommandLine* renderer_cmd) const {
+    base::CommandLine* renderer_cmd) {
   // Propagate the following switches to the renderer command line (along
   // with any associated values) if present in the browser command line.
   static const char* const kSwitchNames[] = {
@@ -1839,7 +1843,13 @@ void RenderProcessHostImpl::PropagateBrowserCommandLineToRenderer(
   renderer_cmd->CopySwitchesFrom(browser_cmd, kSwitchNames,
                                  arraysize(kSwitchNames));
 
+#if defined(OS_WIN)
+  field_trial_state_.reset(new base::SharedMemory());
+  BrowserChildProcessHostImpl::CopyFeatureAndFieldTrialFlags(
+    renderer_cmd, field_trial_state_.get());
+#else
   BrowserChildProcessHostImpl::CopyFeatureAndFieldTrialFlags(renderer_cmd);
+#endif
 
   if (browser_cmd.HasSwitch(switches::kTraceStartup) &&
       BrowserMainLoop::GetInstance()->is_tracing_startup_for_duration()) {