Remove BackForwardClient, cleanup starting a history navigation

Source/core/loader/NavigationScheduler.cpp

Index: Source/core/loader/NavigationScheduler.cpp
diff --git a/Source/core/loader/NavigationScheduler.cpp b/Source/core/loader/NavigationScheduler.cpp
index 6429a416fd7916e02ba55554a363a7caf035cf8e..1a86a8e6176b605c22268b7b05c52ea3f1a37b95 100644
--- a/Source/core/loader/NavigationScheduler.cpp
+++ b/Source/core/loader/NavigationScheduler.cpp
@@ -46,7 +46,6 @@
 #include "core/loader/FrameLoader.h"
 #include "core/loader/FrameLoaderClient.h"
 #include "core/loader/FrameLoaderStateMachine.h"
-#include "core/page/BackForwardClient.h"
 #include "core/page/Page.h"
 #include "platform/SharedBuffer.h"
 #include "platform/UserGestureIndicator.h"
@@ -185,26 +184,6 @@ public:
     }
 };
 
-class ScheduledHistoryNavigation final : public ScheduledNavigation {
-public:
-    explicit ScheduledHistoryNavigation(int historySteps)
-        : ScheduledNavigation(0, false, true)
-        , m_historySteps(historySteps)
-    {
-    }
-
-    virtual void fire(LocalFrame* frame) override
-    {
-        OwnPtr<UserGestureIndicator> gestureIndicator = createUserGestureIndicator();
-        // go(i!=0) from a frame navigates into the history of the frame only,
-        // in both IE and NS (but not in Mozilla). We can't easily do that.
-        frame->page()->deprecatedLocalMainFrame()->loader().client()->navigateBackForward(m_historySteps);
-    }
-
-private:
-    int m_historySteps;
-};
-
 class ScheduledFormSubmission final : public ScheduledNavigation {
 public:
     ScheduledFormSubmission(PassRefPtrWillBeRawPtr<FormSubmission> submission, bool lockBackForwardList)
@@ -340,26 +319,6 @@ void NavigationScheduler::scheduleReload()
     schedule(adoptPtr(new ScheduledReload));
 }
 
-void NavigationScheduler::scheduleHistoryNavigation(int steps)
-{
-    if (!shouldScheduleNavigation())
-        return;
-
-    // Invalid history navigations (such as history.forward() during a new load) have the side effect of cancelling any scheduled
-    // redirects. We also avoid the possibility of cancelling the current load by avoiding the scheduled redirection altogether.
-    BackForwardClient& backForward = m_frame->page()->backForward();
-    if (steps > backForward.forwardListCount() || -steps > backForward.backListCount()) {
-        cancel();

[Nate Chapin, 2014/10/22 19:57:17]

Dropping this cancel() should be the only behavior change of this patch. This
dates back to http://src.chromium.org/viewvc/blink?view=revision&revision=50111,
where it was referred to as a side effect. I don't think it's a desirable or
necessary side effect, but I'm not absolutely certain.

[dcheng, 2014/11/04 19:07:40]

Let's make sure we match the behavior of other browsers. If IE/FF don't cancel
load on an invalid history navigation, then we should definitely match them =)

-        return;
-    }
-
-    // In all other cases, schedule the history traversal to occur asynchronously.
-    if (steps)
-        schedule(adoptPtr(new ScheduledHistoryNavigation(steps)));
-    else
-        schedule(adoptPtr(new ScheduledReload));
-}
-
 void NavigationScheduler::timerFired(Timer<NavigationScheduler>*)
 {
     if (!m_frame->page())