Add WebStateListOrderController to control WebState insertion.

ios/shared/chrome/browser/tabs/web_state_list.mm

Index: ios/shared/chrome/browser/tabs/web_state_list.mm
diff --git a/ios/shared/chrome/browser/tabs/web_state_list.mm b/ios/shared/chrome/browser/tabs/web_state_list.mm
index 1137e81b349d7b4701a395aef542999c55bc0699..b1a440ee0505b12c4dfdac1a2dff9f2691c533ee 100644
--- a/ios/shared/chrome/browser/tabs/web_state_list.mm
+++ b/ios/shared/chrome/browser/tabs/web_state_list.mm
@@ -9,6 +9,7 @@
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #import "ios/shared/chrome/browser/tabs/web_state_list_observer.h"
+#import "ios/shared/chrome/browser/tabs/web_state_list_order_controller.h"
 #import "ios/web/public/navigation_manager.h"
 #import "ios/web/public/web_state/web_state.h"
 
@@ -95,7 +96,8 @@ bool WebStateList::WebStateWrapper::WasOpenedBy(const web::WebState* opener,
 }
 
 WebStateList::WebStateList(WebStateOwnership ownership)
-    : web_state_ownership_(ownership) {}
+    : web_state_ownership_(ownership),
+      order_controller_(base::MakeUnique<WebStateListOrderController>(this)) {}
 
 WebStateList::~WebStateList() = default;
 
@@ -149,6 +151,33 @@ void WebStateList::InsertWebState(int index,
     observer.WebStateInsertedAt(this, web_state, index);
 }
 
+void WebStateList::AddWebState(int index,
+                               ui::PageTransition transition,
+                               web::WebState* web_state,
+                               web::WebState* opener) {
+  if (PageTransitionCoreTypeIs(transition, ui::PAGE_TRANSITION_LINK)) {
+    // Assume WebStates opened via link clicks are part of the same "task" as
+    // their parent and are grouped together, unless the index is forced.
+    if (index == kInvalidIndex)

[marq (ping after 24h), 2017/02/17 13:33:00]

The header says to pass kInvalidIndex to have the webstate appended, but this
does something different.

[sdefresne, 2017/02/20 16:12:56]

Addressed.

+      index = order_controller_->DetermineInsertionIndex(transition, opener);
+  }
+
+  if (index < 0 || count() < index)
+    index = count();
+
+  if (PageTransitionCoreTypeIs(transition, ui::PAGE_TRANSITION_TYPED)) {
+    // Also, any WebState opened at the end of the WebStateList with a "TYPED"
+    // transition inherit groups as well. This covers the cases where the user
+    // creats a New Tab (e.g. Ctrl+T, or clicks the New Tab button), or types

[rohitrao (ping after 24h), 2017/02/17 13:04:12]

creates

[sdefresne, 2017/02/20 16:12:56]

Removed.

+    // in the address bar and presses Alt+Enter. This allows for opening a new
+    // Tab to quickly look up something. When this Tab is closed, the old one

[marq (ping after 24h), 2017/02/17 13:33:00]

Nit: do we need a comment in our iOS code that describes Windows keyboard
commands? Is the usage pattern described here sensible for us at all?

[sdefresne, 2017/02/20 16:12:56]

Removed.

+    // is re-selected, not the next-adjacent.
+    // TODO(crbug.com/661988): Make this work.
+  }
+
+  InsertWebState(index, web_state, opener);
+}
+
 void WebStateList::MoveWebStateAt(int from_index, int to_index) {
   DCHECK(ContainsIndex(from_index));
   DCHECK(ContainsIndex(to_index));