alternate ntp: fix website page jankiness when suggestions show and top bars are hidden

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

 // Copyright (c) 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/browser_view_layout.h"
 
 #include "chrome/browser/ui/browser_finder.h"
 #include "chrome/browser/ui/find_bar/find_bar.h"
 #include "chrome/browser/ui/find_bar/find_bar_controller.h"
+#include "chrome/browser/ui/search/search_model.h"
 #include "chrome/browser/ui/view_ids.h"
 #include "chrome/browser/ui/views/bookmarks/bookmark_bar_view.h"
 #include "chrome/browser/ui/views/download/download_shelf_view.h"
 #include "chrome/browser/ui/views/frame/browser_frame.h"
 #include "chrome/browser/ui/views/frame/browser_view.h"
 #include "chrome/browser/ui/views/frame/contents_container.h"
 #include "chrome/browser/ui/views/immersive_mode_controller.h"
 #include "chrome/browser/ui/views/infobars/infobar_container_view.h"
 #include "chrome/browser/ui/views/tabs/tab_strip.h"
 #include "chrome/browser/ui/views/toolbar_view.h"
 #include "ui/base/hit_test.h"
 #include "ui/gfx/point.h"
 #include "ui/gfx/scrollbar_size.h"
 #include "ui/gfx/size.h"
 #include "ui/views/controls/single_split_view.h"
+#include "ui/views/controls/webview/webview.h"
 
 namespace {
 
 // The visible height of the shadow above the tabs. Clicks in this area are
 // treated as clicks to the frame, rather than clicks to the tab.
 const int kTabShadowSize = 2;
 // The vertical overlap between the TabStrip and the Toolbar.
 const int kToolbarTabStripVerticalOverlap = 3;
 // The number of pixels the bookmark bar should overlap the spacer by if the
 // spacer is visible.
@@ skipping 215 matching lines @@
 
 void BrowserViewLayout::ViewRemoved(views::View* host, views::View* view) {
   switch (view->id()) {
     case VIEW_ID_BOOKMARK_BAR:
       active_bookmark_bar_ = NULL;
       break;
   }
 }
 
 void BrowserViewLayout::Layout(views::View* host) {
+  // Showing instant extended suggestions causes us to temporarily hide any
+  // visible bookmark bar and infobars.  In turn, this hiding would normally
+  // cause the content below the suggestions to shift upwards, which looks
+  // surprising (since from the user's perspective, we're "covering" rather than
+  // "removing" the bookmark bar/infobars).  To prevent this, we save off the
+  // content origin here, then once we finish laying things out, force the
+  // contents to continue to display from that origin.
+  const chrome::search::Mode& mode = browser()->search_model()->mode();
+  views::WebView* contents = browser_view_->contents_container_;
+  int preview_height = contents_container_->preview_height();
+  gfx::Point old_contents_origin;
+  if (preview_height > 0 && mode.is_search_suggestions() &&
+      mode.is_origin_default()) {
+    old_contents_origin = contents->bounds().origin();
+    views::View::ConvertPointToTarget(contents->parent(), browser_view_,
+                                      &old_contents_origin);
+  }
+
   vertical_layout_rect_ = browser_view_->GetLocalBounds();
   int top = LayoutTabStripRegion();
   if (browser_view_->IsTabStripVisible()) {
     int x = browser_view_->tabstrip_->GetMirroredX() +
         browser_view_->GetMirroredX() +
         browser_view_->frame()->GetThemeBackgroundXInset();
     browser_view_->tabstrip_->SetBackgroundOffset(gfx::Point(x,
         browser_view_->frame()->GetTabStripInsets(false).top));
   }
   top = LayoutToolbar(top);
   top = LayoutBookmarkAndInfoBars(top);
   // During immersive mode reveal the content stays near the top of the view.
   if (browser_view_->immersive_mode_controller()->IsRevealed()) {
     top = browser_view_->tabstrip_->y();
     if (!browser_view_->immersive_mode_controller()->hide_tab_indicators())
       top += TabStrip::GetImmersiveHeight();
   }
 
   int bottom = LayoutDownloadShelf(browser_view_->height());
   int active_top_margin = GetTopMarginForActiveContent();
   top -= active_top_margin;
   contents_container_->SetActiveTopMargin(active_top_margin);
   LayoutTabContents(top, bottom);
+
+  // Now set the contents to display at their previous origin if we just hid the
+  // bookmark and/or infobars.
+  if (active_top_margin == 0 && !old_contents_origin.IsOrigin()) {
+    gfx::Point new_contents_origin(contents->bounds().origin());
+    views::View::ConvertPointToTarget(contents->parent(), browser_view_,
+                                      &new_contents_origin);
+    active_top_margin = old_contents_origin.y() - new_contents_origin.y();
+    // Special case: While normally the suggestions appear to "cover" any
+    // bookmark/infobars, if the suggestions are very short, they might not
+    // fully cover that gap, and leaving the contents at their original height
+    // would leave an odd-looking blank space.  In this case, we allow the
+    // contents to go ahead and shift upward.
+    if (active_top_margin > 0 && active_top_margin < preview_height)
+      contents_container_->SetActiveTopMargin(active_top_margin);
+  }
+
   // This must be done _after_ we lay out the WebContents since this
   // code calls back into us to find the bounding box the find bar
   // must be laid out within, and that code depends on the
   // TabContentsContainer's bounds being up to date.
   if (browser()->HasFindBarController()) {
     browser()->GetFindBarController()->find_bar()->MoveWindowIfNecessary(
         gfx::Rect(), true);
   }
 }
 
@@ skipping 20 matching lines @@
     tabstrip->SetVisible(false);
     tabstrip->SetBounds(0, 0, 0, 0);
     return 0;
   }
   // This retrieves the bounds for the tab strip based on whether or not we show
   // anything to the left of it, like the incognito avatar.
   gfx::Rect tabstrip_bounds(
       browser_view_->frame()->GetBoundsForTabStrip(tabstrip));
   gfx::Point tabstrip_origin(tabstrip_bounds.origin());
   views::View::ConvertPointToTarget(browser_view_->parent(), browser_view_,
-                                  &tabstrip_origin);
+                                    &tabstrip_origin);
   tabstrip_bounds.set_origin(tabstrip_origin);
 
   tabstrip->SetVisible(true);
   tabstrip->SetBoundsRect(tabstrip_bounds);
   int bottom = tabstrip_bounds.bottom();
 
   // The metro window switcher sits at the far right edge of the tabstrip
   // a |kWindowSwitcherOffsetX| pixels from the right edge.
   // Only visible if there is more than one type of window to switch between.
   // TODO(mad): update this code when more window types than just incognito
@@ skipping 162 matching lines @@
   }
   return bottom;
 }
 
 bool BrowserViewLayout::InfobarVisible() const {
   views::View* infobar_container = browser_view_->infobar_container_;
   // NOTE: Can't check if the size IsEmpty() since it's always 0-width.
   return browser()->SupportsWindowFeature(Browser::FEATURE_INFOBAR) &&
       (infobar_container->GetPreferredSize().height() != 0);
 }