[Android] Isolate OverscrollRefresh from device density

content/browser/android/overscroll_controller_android.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/android/overscroll_controller_android.h"
 
 #include "base/android/build_info.h"
 #include "base/bind.h"
 #include "cc/layers/layer.h"
 #include "cc/output/compositor_frame_metadata.h"
 #include "content/browser/android/edge_effect.h"
 #include "content/browser/android/edge_effect_l.h"
 #include "content/common/input/did_overscroll_params.h"
 #include "content/public/browser/web_contents.h"
 #include "third_party/WebKit/public/web/WebInputEvent.h"
 #include "ui/base/android/window_android_compositor.h"
 
 namespace content {
 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) {
   DCHECK(resource_manager);
   static bool use_l_flavoured_effect =
       base::android::BuildInfo::GetInstance()->sdk_int() >= kAndroidLSDKVersion;
   if (use_l_flavoured_effect)
     return scoped_ptr<EdgeEffectBase>(new EdgeEffectL(resource_manager));
 
   return scoped_ptr<EdgeEffectBase>(
       new EdgeEffect(resource_manager, dpi_scale));
 }
 
 }  // namespace
 
 OverscrollControllerAndroid::OverscrollControllerAndroid(
     WebContents* web_contents,
     ui::WindowAndroidCompositor* compositor,
     float dpi_scale)
     : WebContentsObserver(web_contents),
       compositor_(compositor),
       dpi_scale_(dpi_scale),
       enabled_(true),
       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);
 }
 
 OverscrollControllerAndroid::~OverscrollControllerAndroid() {
 }
 
 bool OverscrollControllerAndroid::WillHandleGestureEvent(
     const blink::WebGestureEvent& event) {
   if (!enabled_)
@@ skipping 156 matching lines @@
 
 bool OverscrollControllerAndroid::IsStillRefreshing() const {
   return triggered_refresh_active_;
 }
 
 void OverscrollControllerAndroid::SetNeedsAnimate() {
   compositor_->SetNeedsAnimate();
 }
 
 }  // namespace content