webview: fold function which is only used once

No functional change.

Bug: None
Change-Id: Ie077b642c13f5b4b88f7940250912c6b032285cb
Reviewed-on: https://chromium-review.googlesource.com/873632Reviewed-by: Richard Coles <torne@chromium.org>
Commit-Queue: Thiemo Nagel <tnagel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#533304}

android_webview/common/aw_content_client.cc

@@ -32,13 +32,7 @@ std::string GetUserAgent() {
         switches::kUseMobileUserAgent)) {
     product += " Mobile";
   }
-  return content::BuildUserAgentFromProductAndExtraOSInfo(
-          product,
-          GetExtraOSUserAgentInfo());
-}
-
-std::string GetExtraOSUserAgentInfo() {
-  return "; wv";
+  return content::BuildUserAgentFromProductAndExtraOSInfo(product, "; wv");
 }
 
 void AwContentClient::AddAdditionalSchemes(Schemes* schemes) {

android_webview/common/aw_content_client.h

@@ -17,8 +17,6 @@ namespace android_webview {
 
 std::string GetProduct();
 std::string GetUserAgent();
-// extra text to be put into the OS section of the user agent text
-std::string GetExtraOSUserAgentInfo();
 
 class AwContentClient : public content::ContentClient {
  public: