Enabling overscroll/GestureNav for Athena.

athena/content/web_activity.cc

Index: athena/content/web_activity.cc
diff --git a/athena/content/web_activity.cc b/athena/content/web_activity.cc
index 95ddd35b862b73df8c402a4e2636263b6992e640..7329546db1bcc51698ae0bd988f8ee65baf2fec2 100644
--- a/athena/content/web_activity.cc
+++ b/athena/content/web_activity.cc
@@ -7,11 +7,13 @@
 #include "athena/activity/public/activity_factory.h"
 #include "athena/activity/public/activity_manager.h"
 #include "athena/input/public/accelerator_manager.h"
+#include "base/command_line.h"
 #include "base/strings/utf_string_conversions.h"
 #include "content/public/browser/native_web_keyboard_event.h"
 #include "content/public/browser/navigation_controller.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_delegate.h"
+#include "content/public/common/content_switches.h"
 #include "ui/views/controls/webview/unhandled_keyboard_event_handler.h"
 #include "ui/views/controls/webview/webview.h"
 #include "ui/views/focus/focus_manager.h"
@@ -220,6 +222,12 @@ class AthenaWebView : public views::WebView {
     return NULL;
   }
 
+  virtual bool CanOverscrollContent() const OVERRIDE {
+    const std::string value = CommandLine::ForCurrentProcess()->
+        GetSwitchValueASCII(switches::kOverscrollHistoryNavigation);
+    return value != "0";

[oshima, 2014/08/29 20:00:37]

just out of curiosity, do you know why this flag uses 1/0 value instead of just
a flag?

[mfomitchev, 2014/08/29 20:40:50]

It's actually 0/1/2.
0 = off
1 = on, default screenshot-based UI
2 = on, simple UI with no screenshots used. It shows navigation arrows that
slide in on the side when overscrolling.

[oshima, 2014/08/29 20:53:49]

I see. Would you mind updating the comment in


https://code.google.com/p/chromium/codesearch#chromium/src/content/public/com...

in separate CL?

[mfomitchev, 2014/08/29 21:15:21]

Done: https://codereview.chromium.org/519143002/

+  }
+
   virtual void AddNewContents(content::WebContents* source,
                               content::WebContents* new_contents,
                               WindowOpenDisposition disposition,