First step in enabling creating tabs without an Activity on Android.

chrome/browser/chrome_content_browser_client.cc

Index: chrome/browser/chrome_content_browser_client.cc
diff --git a/chrome/browser/chrome_content_browser_client.cc b/chrome/browser/chrome_content_browser_client.cc
index 558d739fef88ca3df3e29bc61b303f012b1109b3..7caf39d87aff9142703a8c0a7daaad02d1ec79c2 100644
--- a/chrome/browser/chrome_content_browser_client.cc
+++ b/chrome/browser/chrome_content_browser_client.cc
@@ -156,6 +156,7 @@
 #include "chrome/browser/chrome_browser_main_linux.h"
 #elif defined(OS_ANDROID)
 #include "chrome/browser/android/new_tab_page_url_handler.h"
+#include "chrome/browser/android/service_tab_launcher.h"
 #include "chrome/browser/android/webapps/single_tab_mode_tab_helper.h"
 #include "chrome/browser/chrome_browser_main_android.h"
 #include "chrome/common/descriptors_android.h"
@@ -2509,9 +2510,10 @@ bool ChromeContentBrowserClient::CheckMediaAccessPermission(
           browser_context, security_origin, type);
 }
 
-content::WebContents* ChromeContentBrowserClient::OpenURL(
+void ChromeContentBrowserClient::OpenURL(
     content::BrowserContext* browser_context,
-    const content::OpenURLParams& params) {
+    const content::OpenURLParams& params,
+    base::Callback<void(content::WebContents*)> callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
 #if !defined(OS_ANDROID) && !defined(OS_IOS)
@@ -2522,12 +2524,15 @@ content::WebContents* ChromeContentBrowserClient::OpenURL(
   nav_params.user_gesture = params.user_gesture;
 
   Navigate(&nav_params);
-  return nav_params.target_contents;
+  callback.Run(nav_params.target_contents);
+#elif defined(OS_ANDROID)
+  chrome::android::ServiceTabLauncher::GetInstance()->LaunchTab(
+      browser_context, params, callback);
 #else
-  // TODO(mlamouri): write a chrome::Navigate() method for Android and iOS.
+  // TODO(mlamouri): write a chrome::Navigate() method for iOS.
   // See https://crbug.com/448409.

[mlamouri (slow - plz ping), 2015/02/09 12:07:37]

I think you can remove the TODO and the mention of the BUG. Just change the
comment to note that we do not support this on iOS.

[Peter Beverloo, 2015/02/10 17:49:37]

Done.

-  return nullptr;
-#endif // !defined(OS_ANDROID) && !defined(OS_IOS)
+  NOTIMPLEMENTED();
+#endif
 }
 
 content::DevToolsManagerDelegate*