Hide location bar on WebKit programmatic scroll.

cc/top_controls_manager.cc

 // Copyright 2013 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 "cc/top_controls_manager.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
 #include "base/time.h"
@@ skipping 16 matching lines @@
 scoped_ptr<TopControlsManager> TopControlsManager::Create(
     TopControlsManagerClient* client, float top_controls_height) {
   return make_scoped_ptr(new TopControlsManager(client, top_controls_height));
 }
 
 TopControlsManager::TopControlsManager(TopControlsManagerClient* client,
                                        float top_controls_height)
     : client_(client),
       animation_direction_(NO_ANIMATION),
       is_overlay_mode_(false),
-      scroll_readjustment_enabled_(false),
       top_controls_height_(top_controls_height),
       controls_top_offset_(0),
       content_top_offset_(top_controls_height),
-      previous_root_scroll_offset_(0.f) {
+      in_user_scroll_(false) {
   CHECK(client_);
 }
 
 TopControlsManager::~TopControlsManager() {
 }
 
-void TopControlsManager::UpdateDrawPositions() {
-  if (!client_->haveRootScrollLayer())
+void TopControlsManager::ProgrammaticScroll(gfx::Vector2d targetOffset) {
+  if (controls_top_offset_ == -top_controls_height_)
     return;
 
-  // If the scroll position has changed underneath us (i.e. a javascript
-  // scroll), then simulate a scroll that covers the delta.
-  float scroll_total_y = RootScrollLayerTotalScrollY();
-  if (scroll_readjustment_enabled_
-      && scroll_total_y != previous_root_scroll_offset_) {
-    ScrollBy(gfx::Vector2dF(0, scroll_total_y - previous_root_scroll_offset_));
-    StartAnimationIfNecessary();
-    previous_root_scroll_offset_ = RootScrollLayerTotalScrollY();
-  }
+  // We're in a user scroll.
+  if (in_user_scroll_)
+      return;
+
+  ScrollBy(gfx::Vector2dF(0, top_controls_height_));

[Ted C, 2013/01/24 22:01:01]

hmm...so any javascript scroll will attempt to hide the top controls?  This
should definitely do the trick, but I thought it was only supposed to be limited
to scroll(0,0) or scroll(0,1), but I guess maybe that is what you were saying in
the recent meeting where all types of things hide the top controls.

[John Knottenbelt, 2013/01/30 16:08:45]

We can restrict it here to just 0,0 and 0,1 if we decide that this is what we
really want, but I think hiding on any programmatic scroll matches existing
mobile browsers behaviour more closely. 

On 2013/01/24 22:01:01, Ted C wrote:

+  StartAnimationIfNecessary();

[Ted C, 2013/01/24 22:01:01]

The start animation if necessary shouldn't be required as you should also be
hiding it entirely.

If you want it to always hide the controls but animate it, you should be able to
replace both of these lines with this:
SetupAnimation(HIDING_CONTROLS)

[John Knottenbelt, 2013/01/30 16:08:45]

Done.

 }
 
 void TopControlsManager::ScrollBegin() {
   ResetAnimations();
-  scroll_readjustment_enabled_ = false;
+  in_user_scroll_ = true;
 }
 
 gfx::Vector2dF TopControlsManager::ScrollBy(
     const gfx::Vector2dF pending_delta) {
   ResetAnimations();
   return ScrollInternal(pending_delta);
 }
 
 gfx::Vector2dF TopControlsManager::ScrollInternal(
     const gfx::Vector2dF pending_delta) {
@@ skipping 30 matching lines @@
       || previous_content_offset != content_top_offset_) {
     client_->setNeedsRedraw();
     client_->setNeedsUpdateDrawProperties();
   }
 
   return pending_delta - applied_delta;
 }
 
 void TopControlsManager::ScrollEnd() {
   StartAnimationIfNecessary();
-  previous_root_scroll_offset_ = RootScrollLayerTotalScrollY();
-  scroll_readjustment_enabled_ = true;
+  in_user_scroll_ = false;
 }
 
 void TopControlsManager::Animate(base::TimeTicks monotonic_time) {
   if (!top_controls_animation_ || !client_->haveRootScrollLayer())
     return;
 
   double time = (monotonic_time - base::TimeTicks()).InMillisecondsF();
   float new_offset = top_controls_animation_->getValue(time);
   gfx::Vector2dF scroll_vector(0.f, -(new_offset - controls_top_offset_));
   ScrollInternal(scroll_vector);
@@ skipping 54 matching lines @@
 
   if ((animation_direction_ == SHOWING_CONTROLS && new_offset >= 0) ||
       (animation_direction_ == HIDING_CONTROLS
           && new_offset <= -top_controls_height_)) {
     return true;
   }
   return false;
 }
 
 }  // namespace cc