mac: Always do history swiping on the NTP on lion devices with touchpad.

chrome/browser/renderer_host/chrome_render_widget_host_view_mac_delegate.mm

Index: chrome/browser/renderer_host/chrome_render_widget_host_view_mac_delegate.mm
diff --git a/chrome/browser/renderer_host/chrome_render_widget_host_view_mac_delegate.mm b/chrome/browser/renderer_host/chrome_render_widget_host_view_mac_delegate.mm
index 206a1a2dd19efca76aff3a8899a2ef73bbd1cf13..298bdd710724c3f127ba900ec014a4cf82e95d92 100644
--- a/chrome/browser/renderer_host/chrome_render_widget_host_view_mac_delegate.mm
+++ b/chrome/browser/renderer_host/chrome_render_widget_host_view_mac_delegate.mm
@@ -170,6 +170,18 @@ class SpellCheckRenderViewObserver : public content::RenderViewHostObserver {
   if (isDevtoolsRwhv)
     return NO;
 
+  // TODO(thakis): This is wrong, as it will navigate the frontmost browser
+  // for swipe events on background windows. It also navigates the frontmost
+  // browser for swipes on extensions popups. And it's a dependency problem,
+  // too. http://crbug.com/102541

[Robert Sesek, 2012/01/30 17:13:18]

I think I have a fix for this either today or tomorrow. Yay!

[Nico, 2012/01/30 17:59:22]

Heh, I've been looking at this, too. I guess I'll stop looking then :-)

+  Browser* browser = BrowserList::GetLastActive();
+
+  if (browser && browser->IsOnNtp() &&
+      [NSEvent isSwipeTrackingFromScrollEventsEnabled]) {
+    // Always do history navigation on the NTP if it's enabled.
+    gotUnhandledWheelEvent_ = true;
+  }
+
   if (gotUnhandledWheelEvent_ &&
       [NSEvent isSwipeTrackingFromScrollEventsEnabled] &&
       [theEvent phase] == NSEventPhaseChanged) {
@@ -182,7 +194,7 @@ class SpellCheckRenderViewObserver : public content::RenderViewHostObserver {
     bool isRightScroll = [theEvent scrollingDeltaX] < 0;
     bool goForward = isRightScroll;
     bool canGoBack = false, canGoForward = false;
-    if (Browser* browser = BrowserList::GetLastActive()) {
+    if (browser) {
       canGoBack = browser->CanGoBack();
       canGoForward = browser->CanGoForward();
     }
@@ -263,7 +275,7 @@ class SpellCheckRenderViewObserver : public content::RenderViewHostObserver {
       return YES;
     }
   }
-  return NO;
+  return gotUnhandledWheelEvent_;
 }
 
 - (BOOL)validateUserInterfaceItem:(id<NSValidatedUserInterfaceItem>)item