Fix command-line override of the User-Agent product component (see issue #2622).

When the NetworkService is enabled the U-A string is configured via
SystemNetworkContextManager::CreateDefaultNetworkContextParams, which calls
chrome_content_browser_client.cc GetUserAgent(). This change modifies the Chrome
implementation to match CEF, so that the U-A product component can still be
overridden via the `--product-version` command-line flag.

To test: Verify that chrome://version, navigator.userAgent (JS executed from
DevTools console) and network requests (headers shown in DevTools Network tab)
show the expected User-Agent value in the following cases:
- Running `cefclient --enable-network-service --user-agent="<value>"`
- Running `cefclient --enable-network-service --product-version="<value>"`

libcef/browser/content_browser_client.cc

@@ -56,6 +56,7 @@
 #include "base/threading/thread_restrictions.h"
 #include "cef/grit/cef_resources.h"
 #include "chrome/browser/browser_process.h"
+#include "chrome/browser/chrome_content_browser_client.h"
 #include "chrome/browser/chrome_service.h"
 #include "chrome/browser/net/system_network_context_manager.h"
 #include "chrome/browser/plugins/plugin_info_host_impl.h"
@@ -1371,27 +1372,19 @@ bool CefContentBrowserClient::HandleExternalProtocol(
 }
 
 std::string CefContentBrowserClient::GetProduct() const {
-  const base::CommandLine* command_line =
-      base::CommandLine::ForCurrentProcess();
-  if (command_line->HasSwitch(switches::kProductVersion))
-    return command_line->GetSwitchValueASCII(switches::kProductVersion);
-
-  return GetChromeProduct();
+  // Match the logic in chrome_content_browser_client.cc GetProduct() which
+  // will be called when the NetworkService is enabled.
+  return ::GetProduct();
 }
 
 std::string CefContentBrowserClient::GetChromeProduct() const {
-  return base::StringPrintf("Chrome/%d.%d.%d.%d", CHROME_VERSION_MAJOR,
-                            CHROME_VERSION_MINOR, CHROME_VERSION_BUILD,
-                            CHROME_VERSION_PATCH);
+  return version_info::GetProductNameAndVersionForUserAgent();
 }
 
 std::string CefContentBrowserClient::GetUserAgent() const {
-  const base::CommandLine* command_line =
-      base::CommandLine::ForCurrentProcess();
-  if (command_line->HasSwitch(switches::kUserAgent))
-    return command_line->GetSwitchValueASCII(switches::kUserAgent);
-
-  return content::BuildUserAgentFromProduct(GetProduct());
+  // Match the logic in chrome_content_browser_client.cc GetUserAgent() which
+  // will be called when the NetworkService is enabled.
+  return ::GetUserAgent();
 }
 
 blink::UserAgentMetadata CefContentBrowserClient::GetUserAgentMetadata() const {

patch/patch.cfg

@@ -244,6 +244,12 @@ patches = [
     # https://bitbucket.org/chromiumembedded/cef/issues/2613
     'name': 'chrome_browser_net_export',
   },
+  {
+    # Support override of the User-Agent product component when NetworkService
+    # is enabled.
+    # https://bitbucket.org/chromiumembedded/cef/issues/2622
+    'name': 'chrome_browser_product_override',
+  },
   {
     # Allow CEF to share Chrome plugin loading code.
     'name': 'chrome_plugins',

patch/patches/chrome_browser_product_override.patch

@@ -0,0 +1,37 @@
+diff --git chrome/browser/chrome_content_browser_client.cc chrome/browser/chrome_content_browser_client.cc
+index 52a1a31ee131..5a1e29fec9c8 100644
+--- chrome/browser/chrome_content_browser_client.cc
++++ chrome/browser/chrome_content_browser_client.cc
+@@ -1033,12 +1033,16 @@ void LaunchURL(
+   }
+ }
+ 
++}  // namespace
++
+ std::string GetProduct() {
++  base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
++  if (command_line->HasSwitch(switches::kProductVersion))
++    return command_line->GetSwitchValueASCII(switches::kProductVersion);
++
+   return version_info::GetProductNameAndVersionForUserAgent();
+ }
+ 
+-}  // namespace
+-
+ std::string GetUserAgent() {
+   base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
+   if (command_line->HasSwitch(switches::kUserAgent)) {
+diff --git chrome/browser/chrome_content_browser_client.h chrome/browser/chrome_content_browser_client.h
+index cbf1e2218e91..a42d2a4d71bb 100644
+--- chrome/browser/chrome_content_browser_client.h
++++ chrome/browser/chrome_content_browser_client.h
+@@ -77,7 +77,8 @@ class Origin;
+ 
+ class ChromeSerialDelegate;
+ 
+-// Returns the user agent of Chrome.
++// Returns the product and user agent of Chrome.
++std::string GetProduct();
+ std::string GetUserAgent();
+ 
+ blink::UserAgentMetadata GetUserAgentMetadata();