Revert 255858 "Simplify the user agent code some more since afte..."

There are some browser_tests failures on the buildbots that don't reproduce locally. Reverting while I investigate.

> Simplify the user agent code some more since after r255534 it's not affected by the site's URL.
> 
> Code in content always gets it now from ContentClient::GetUserAgent. In Chrome, there's a GetUserAgent function which returns it.
> 
> BUG=338338
> R=isherman@chromium.org, pauljensen@chromium.org, scottmg@chromium.org, tfarina@chromium.org
> 
> Review URL: https://codereview.chromium.org/191093002

TBR=jam@chromium.org

Review URL: https://codereview.chromium.org/192283002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255867 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 17 insertions, 0 deletions

diff --git a/content/app/content_main_runner.cc b/content/app/content_main_runner.cc
index 13d112ab..aca3c79 100644
--- a/content/app/content_main_runner.cc
+++ b/content/app/content_main_runner.cc
@@ -51,6 +51,7 @@
 #include "ui/base/ui_base_paths.h"
 #include "ui/base/ui_base_switches.h"
 #include "ui/gfx/win/dpi.h"
+#include "webkit/common/user_agent/user_agent.h"
 
 #if defined(USE_TCMALLOC)
 #include "third_party/tcmalloc/chromium/src/gperftools/malloc_extension.h"
@@ -379,6 +380,14 @@ int RunZygote(const MainFunctionParams& main_function_params,
       command_line.GetSwitchValueASCII(switches::kProcessType);
   ContentClientInitializer::Set(process_type, delegate);
 
+  // If a custom user agent was passed on the command line, we need
+  // to (re)set it now, rather than using the default one the zygote
+  // initialized.
+  if (command_line.HasSwitch(switches::kUserAgent)) {
+    webkit_glue::SetUserAgent(
+        command_line.GetSwitchValueASCII(switches::kUserAgent));
+  }
+
   // The StatsTable must be initialized in each process; we already
   // initialized for the browser process, now we need to initialize
   // within the new processes as well.
@@ -738,6 +747,14 @@ class ContentMainRunnerImpl : public ContentMainRunner {
     if (delegate_)
       delegate_->PreSandboxStartup();
 
+    // Set any custom user agent passed on the command line now so the string
+    // doesn't change between calls to webkit_glue::GetUserAgent(), otherwise it
+    // defaults to the user agent set during SetContentClient().
+    if (command_line.HasSwitch(switches::kUserAgent)) {
+      webkit_glue::SetUserAgent(
+          command_line.GetSwitchValueASCII(switches::kUserAgent));
+    }
+
     if (!process_type.empty())
       CommonSubprocessInit(process_type);