Bunch of match preview tweaks:

chrome/browser/views/frame/browser_view_layout.cc

Index: chrome/browser/views/frame/browser_view_layout.cc
diff --git a/chrome/browser/views/frame/browser_view_layout.cc b/chrome/browser/views/frame/browser_view_layout.cc
index 0abd70e78f2e63aa83e72006632c3388f67b41b5..ae71abe1ff8f2ffe7e675e466f915b223a89ec00 100644
--- a/chrome/browser/views/frame/browser_view_layout.cc
+++ b/chrome/browser/views/frame/browser_view_layout.cc
@@ -12,6 +12,7 @@
 #include "chrome/browser/views/download_shelf_view.h"
 #include "chrome/browser/views/frame/browser_frame.h"
 #include "chrome/browser/views/frame/browser_view.h"
+#include "chrome/browser/views/frame/contents_container.h"
 #include "chrome/browser/views/tabs/side_tab_strip.h"
 #include "chrome/browser/views/tabs/tab_strip.h"
 #include "chrome/browser/views/toolbar_view.h"
@@ -206,15 +207,18 @@ void BrowserViewLayout::Uninstalled(views::View* host) {}
 void BrowserViewLayout::ViewAdded(views::View* host, views::View* view) {
   switch (view->GetID()) {
     case VIEW_ID_CONTENTS_SPLIT: {
-        contents_split_ = view;
-        if (SidebarManager::IsSidebarAllowed()) {
-          views::View* sidebar_split = contents_split_->GetChildViewAt(0);
-          contents_container_ = sidebar_split->GetChildViewAt(0);
-        } else {
-          contents_container_ = contents_split_->GetChildViewAt(0);
-        }
+      contents_split_ = view;
+      // TODO: this is fragile, fix.
+      if (SidebarManager::IsSidebarAllowed()) {
+        views::View* sidebar_split = contents_split_->GetChildViewAt(0);
+        contents_container_ = static_cast<ContentsContainer*>(
+            sidebar_split->GetChildViewAt(0));
+      } else {
+        contents_container_ = static_cast<ContentsContainer*>(
+            contents_split_->GetChildViewAt(0));
       }
       break;
+    }
     case VIEW_ID_INFO_BAR_CONTAINER:
       infobar_container_ = view;
       break;
@@ -252,6 +256,10 @@ void BrowserViewLayout::Layout(views::View* host) {
   top = LayoutToolbar(top);
   top = LayoutBookmarkAndInfoBars(top);
   int bottom = LayoutDownloadShelf(browser_view_->height());
+  int active_top_margin = GetTopMarginForActiveContent();
+  top -= active_top_margin;
+  bottom += active_top_margin;
+  contents_container_->SetActiveTopMargin(active_top_margin);
   LayoutTabContents(top, bottom);
   // This must be done _after_ we lay out the TabContents since this
   // code calls back into us to find the bounding box the find bar
@@ -276,6 +284,14 @@ gfx::Size BrowserViewLayout::GetPreferredSize(views::View* host) {
 //////////////////////////////////////////////////////////////////////////////
 // BrowserViewLayout, private:
 
+Browser* BrowserViewLayout::browser() {
+  return browser_view_->browser();
+}
+
+const Browser* BrowserViewLayout::browser() const {
+  return browser_view_->browser();
+}
+
 int BrowserViewLayout::LayoutTabStrip() {
   if (!browser_view_->IsTabStripVisible()) {
     tabstrip_->SetVisible(false);
@@ -357,13 +373,31 @@ int BrowserViewLayout::LayoutInfoBar(int top) {
   return top + height;
 }
 
-// Layout the TabContents container, between the coordinates |top| and
-// |bottom|.
 void BrowserViewLayout::LayoutTabContents(int top, int bottom) {
   contents_split_->SetBounds(vertical_layout_rect_.x(), top,
                              vertical_layout_rect_.width(), bottom - top);
 }
 
+int BrowserViewLayout::GetTopMarginForActiveContent() {
+  if (!active_bookmark_bar_ || !browser_view_->IsBookmarkBarVisible() ||
+      !active_bookmark_bar_->IsDetached()) {
+    return 0;
+  }
+
+  if (contents_split_->GetChildViewAt(1) &&
+      contents_split_->GetChildViewAt(1)->IsVisible())
+    return 0;
+
+  if (SidebarManager::IsSidebarAllowed()) {
+    views::View* sidebar_split = contents_split_->GetChildViewAt(0);
+    if (sidebar_split->GetChildViewAt(1) &&
+        sidebar_split->GetChildViewAt(1)->IsVisible())
+      return 0;
+  }
+
+  return active_bookmark_bar_->height();
+}
+
 int BrowserViewLayout::LayoutDownloadShelf(int bottom) {
   // Re-layout the shelf either if it is visible or if it's close animation
   // is currently running.