alternate ntp: fix content origin when overlay shrinks to shorter than top bars

chrome/browser/ui/views/frame/contents_container.cc

 // Copyright 2012 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 "chrome/browser/ui/views/frame/contents_container.h"
 
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/notification_types.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/web_contents.h"
@@ skipping 60 matching lines @@
   }
 
  private:
   gfx::ImageSkia drop_shadow_;
 
   DISALLOW_COPY_AND_ASSIGN(ShadowView);
 };
 
 }  // namespace
 
-ContentsContainer::ContentsContainer(views::WebView* active)
+ContentsContainer::ContentsContainer(views::WebView* active,
+                                     views::View* browser_view)
     : active_(active),
+      browser_view_(browser_view),
       overlay_(NULL),
       overlay_web_contents_(NULL),
       draw_drop_shadow_(false),
       active_top_margin_(0),
       overlay_height_(100),
       overlay_height_units_(INSTANT_SIZE_PERCENT) {
   AddChildView(active_);
 }
 
 ContentsContainer::~ContentsContainer() {
@@ skipping 69 matching lines @@
         content::NotificationSource source =
             content::Source<content::RenderWidgetHost>(rvh);
         registrar_.Add(this,
             content::NOTIFICATION_RENDER_WIDGET_HOST_DID_UPDATE_BACKING_STORE,
             source);
       }
     }
 #endif  // !defined(OS_WIN)
   }
 
+  // If overlay's height has shrunk and |active_top_margin_| was used to

[dhollowa, 2013/04/11 21:56:34]

If |overlay_|'s height...

[kuan, 2013/04/11 23:39:20]

Done.

+  // preserve |active_|'s origin in BrowserViewLayout::Layout(), we need to re-
+  // determine if its origin still needs to be preserved (which only happens if

[dhollowa, 2013/04/11 21:56:34]

...preserved.  This only happens... .  In this case force a re-layout of
BrowserView.

[kuan, 2013/04/11 23:39:20]

Done. i slightly modify "This only happens" to "The origin is only preserved if
..".

+  // overlay is taller than total height of hidden bookmark and info bars), so
+  // force a re-layout of BrowserView.
+  bool layout_browser_view = false;
+  if (overlay_ && active_top_margin_ > 0 && units == INSTANT_SIZE_PIXELS &&
+      height > 0 && height < overlay_height_) {
+    layout_browser_view = true;
+  }
+
   overlay_height_ = height;
   overlay_height_units_ = units;
   draw_drop_shadow_ = draw_drop_shadow;
 
   // Add shadow view if there's overlay and drop shadow is needed.
   // Remove shadow view if there's no overlay.
   // If there's overlay and drop shadow is not needed, that means the partial-
   // height overlay is going to be full-height.  Don't remove the shadow view
   // yet because its view will disappear noticeably faster than the webview-ed
   // overlay is repainted at the full height - when resizing web contents page,
   // RenderWidgetHostViewAura locks the compositor until texture is updated or
   // timeout occurs.  This out-of-sync refresh results in a split second where
   // there's no separator between the overlay and active contents, making the
   // overlay contents erroneously appear to be part of active contents.
   // When the overlay is repainted at the full height, we'll be notified via
   // NOTIFICATION_RENDER_WIDGET_HOST_DID_UPDATE_BACKGING_STORE, at which time
   // the shadow view will be removed.
   if (overlay_ && draw_drop_shadow_) {
 #if !defined(OS_WIN)
     if (!shadow_view_.get())  // Shadow view has not been created.
       shadow_view_.reset(new ShadowView());
     if (!shadow_view_->parent())  // Shadow view has not been added.
       AddChildView(shadow_view_.get());
 #endif  // !defined(OS_WIN)
   } else if (!overlay_) {
     shadow_view_.reset();
   }
 
   Layout();
+
+  if (layout_browser_view)
+    browser_view_->Layout();

[dhollowa, 2013/04/11 21:56:34]

Doesn't browser_view_ contain |this| as a view?  So, shouldn't it be:

  if (layout_browser_view)
    browser_view_->Layout();
  else
    Layout();

To avoid a double-layout of |this|?

[kuan, 2013/04/11 23:39:20]

the overlay needs to be laid out before BrowserViewLayout::Layout is called,
'cos the latter retrieves the overlay height before it lays out the children
(see beginning of function in browser_view_layout.cc).

[kuan, 2013/04/11 23:45:24]

hm.. let me try to change BrowserViewLayout::Layout to see if i can get the
overlay height later.

 }
 
 void ContentsContainer::MaybeStackOverlayAtTop() {
   if (!overlay_)
     return;
   // To force |overlay_| to the topmost in the z-order, remove it, then add it
   // back.
   // See comments in SetOverlay() for why shadow view is removed.
   bool removed_shadow = false;
   if (shadow_view_.get()) {
@@ skipping 70 matching lines @@
   DCHECK_EQ(content::NOTIFICATION_RENDER_WIDGET_HOST_DID_UPDATE_BACKING_STORE,
             type);
   // Remove shadow view if it's not needed.
   if (overlay_ && !draw_drop_shadow_) {
     DCHECK(overlay_web_contents_);
     DCHECK_EQ(overlay_web_contents_->GetRenderViewHost(),
               (content::Source<content::RenderWidgetHost>(source)).ptr());
     shadow_view_.reset();
   }
 }