crbug.com/127841 - Request Tablet Site on CB with touch screen.

webkit/glue/user_agent.cc

Index: webkit/glue/user_agent.cc
diff --git a/webkit/glue/user_agent.cc b/webkit/glue/user_agent.cc
index 516504081f136db4e1551c71f4a3237b020e373e..79151e547dd76205621667b26ad56f0313ab5cca 100644
--- a/webkit/glue/user_agent.cc
+++ b/webkit/glue/user_agent.cc
@@ -28,6 +28,11 @@ base::LazyInstance<std::string>::Leaky g_os_info = LAZY_INSTANCE_INITIALIZER;
 }  // namespace
 #endif
 
+namespace {
+const char kUserAgentOverrideForTabletSite[] =
+    "(Linux; Android 4.0.4; Galaxy Nexus Build/IMM76B)";

[Charlie Reis, 2012/08/13 20:38:46]

Do we really want this hard coded?

[gone, 2012/08/13 20:45:12]

I'm not sure if there's a good option other than setting sensible defaults.  The
information about the build type and OS version come directly from Android
itself, which isn't available when you're running ChromeOS.

[gone, 2012/08/14 01:15:16]

Though there is one issue with this: a Galaxy Nexus is a phone.  You should
stick in tablet name in there.

[sschmitz, 2012/09/06 16:44:02]

This has been cleaned up & shortened to "Linux; Android"

+}
+
 namespace webkit_glue {
 
 std::string GetWebKitVersion() {
@@ -162,4 +167,29 @@ void SetUserAgentOSInfo(const std::string& os_info) {
 }
 #endif
 
+std::string BuildUserAgentOverrideForTabletSiteFromUserAgent(
+    const std::string& user_agent) {
+  // Example: original user agent text:
+  //
+  //   Mozilla/5.0 (X11; CrOS x86_64 0.4.0)
+  //   AppleWebKit/537.2 (KHTML, like Gecko) Chrome/22.0.1211.0 Safari/537.2
+  //
+  // Copy & Edit to create user agent override text by replacing
+  //   the text within the first pair of "()". For example:
+  //
+  //   Mozilla/5.0 (Linux; Android 4.0.4; Galaxy Nexus Build/IMM76B)
+  //   AppleWebKit/537.2 (KHTML, like Gecko) Chrome/22.0.1211.0 Safari/537.2
+  //
+  size_t p1 = user_agent.find("(");

[jamesr, 2012/08/07 19:49:03]

This seems pretty gross.

If you look at what's going on here, the browser code is first getting the user
agent string by calling content::GetUserAgent(), which plumbs down eventually
into webkit_glue, and then calling back into webkit_glue again to rewrite part
of it. I think it would be a lot cleaner if you only made one call through this
stack to build the UA string you want.  Take a look at UserAgentState in
webkit_glue.cc - it has logic to build different UA strings for different
situations.

I think I'd prefer plumbing through a way to ask for a specific UA string from
up in chrome/browser/ui/browser_commands.cc with just one call.  You could
expose different GetUserAgent() calls (GetUserAgentForTablet() perhaps) or
provide a parameter to GetUserAgent indicating which UA string you want, or
something of that nature.  You can cache these alternate UA strings on
UserAgentState like we do for user_agent_for_spoofing_hack_.

[sschmitz, 2012/09/06 16:44:02]

This has been cleaned up thanks to Dan's work.
Done.

+  if (p1 != std::string::npos) {
+    size_t p2 = user_agent.find(")", p1);
+    if (p2 != std::string::npos) {
+      std::string ua_override(user_agent);
+      ua_override.replace(p1, p2-p1+1, kUserAgentOverrideForTabletSite);
+      return ua_override;
+    }
+  }
+  return std::string();
+}
+
 }  // namespace webkit_glue