Move gin and v8 portion of profiling to child from common

chrome/app/chrome_main_delegate.cc

Index: chrome/app/chrome_main_delegate.cc
diff --git a/chrome/app/chrome_main_delegate.cc b/chrome/app/chrome_main_delegate.cc
index 5f8dea5917de3846cccec9c86598bc1b1b695f6d..7524657d0544667e2e76c0aedecaeea965bf2571 100644
--- a/chrome/app/chrome_main_delegate.cc
+++ b/chrome/app/chrome_main_delegate.cc
@@ -26,6 +26,7 @@
 #include "build/build_config.h"
 #include "chrome/browser/chrome_content_browser_client.h"
 #include "chrome/browser/defaults.h"
+#include "chrome/child/child_profiling.h"
 #include "chrome/common/channel_info.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_content_client.h"
@@ -528,6 +529,9 @@ bool ChromeMainDelegate::BasicStartupComplete(int* exit_code) {
   chrome::common::mac::EnableCFBundleBlocker();
 #endif
 
+#if !defined(CHROME_MULTIPLE_DLL_BROWSER)

[Nico, 2017/01/13 21:01:19]

if this is mechanical, why does this have the !defined but the other place below
doesn't? (feels like a stupid question, sorry)

[scottmg, 2017/01/13 21:55:08]

You're right, not entirely mechanical I guess. This one runs on all
platforms(-ish). This code is built twice on Windows, once for child and once
for browser, so the define breaks the dependency on the child-only code when
it's built for the browser.

The Zygote one below is in #if POSIX. Strictly speaking I guess it could have
!CHROME_MULTIPLE_DLL_BROWSER too, but it would be more confusing than anything
because that define only really makes sense on Windows.

[Nico, 2017/01/17 13:10:42]

Maybe add a comment explaining why this is ifdef'd and the other isn't (but up
to you; if you think it's more confusing with a comment, omit it)

+  ChildProfiling::ProcessStarted();
+#endif
   Profiling::ProcessStarted();
 
   base::trace_event::TraceLog::GetInstance()->SetArgumentFilterPredicate(
@@ -1017,6 +1021,7 @@ void ChromeMainDelegate::ZygoteStarting(
 }
 
 void ChromeMainDelegate::ZygoteForked() {
+  ChildProfiling::ProcessStarted();
   Profiling::ProcessStarted();
   if (Profiling::BeingProfiled()) {
     base::debug::RestartProfilingAfterFork();