[Android] Isolate OverscrollRefresh from device density

content/browser/android/overscroll_controller_android.cc

Index: content/browser/android/overscroll_controller_android.cc
diff --git a/content/browser/android/overscroll_controller_android.cc b/content/browser/android/overscroll_controller_android.cc
index 5dda6d14eb6256c87fba2650a1b61215ebe14fd3..b32d809ef330cab97e5791c8e382f00bc1dd279d 100644
--- a/content/browser/android/overscroll_controller_android.cc
+++ b/content/browser/android/overscroll_controller_android.cc
@@ -21,6 +21,10 @@ namespace {
 // Used for conditional creation of EdgeEffect types for the overscroll glow.
 const int kAndroidLSDKVersion = 21;
 
+// Default offset in dips from the top of the view beyond which the refresh
+// action will be activated.
+const int kDefaultRefreshDragTargetDips = 64;
+
 scoped_ptr<EdgeEffectBase> CreateGlowEdgeEffect(
     ui::SystemUIResourceManager* resource_manager,
     float dpi_scale) {
@@ -47,7 +51,9 @@ OverscrollControllerAndroid::OverscrollControllerAndroid(
       glow_effect_(base::Bind(&CreateGlowEdgeEffect,
                               &compositor->GetSystemUIResourceManager(),
                               dpi_scale_)),
-      refresh_effect_(&compositor->GetSystemUIResourceManager(), this),
+      refresh_effect_(&compositor->GetSystemUIResourceManager(),
+                      this,
+                      kDefaultRefreshDragTargetDips * dpi_scale),
       triggered_refresh_active_(false) {
   DCHECK(web_contents);
 }