Tweaks to tab overview to get it performant:

. Delay getting thumnbails until 300ms after the window is shown. This
  is necessary as getting the thumnbails is very expensive.
. Configure the thumnbail for one cell at a time. For same reason as
  last one.
. Don't show new tab window widget as we don't yet have the type set
  up.

BUG=none
TEST=none

Review URL: http://codereview.chromium.org/147174

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@19340 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 71 insertions, 6 deletions

diff --git a/chrome/browser/views/tabs/tab_overview_cell.cc b/chrome/browser/views/tabs/tab_overview_cell.cc
index b0b5f9f..0dc46e5 100644
--- a/chrome/browser/views/tabs/tab_overview_cell.cc
+++ b/chrome/browser/views/tabs/tab_overview_cell.cc
@@ -25,7 +25,7 @@ static const int kThumbnailWidth = 220;
 // Padding between favicon/title and thumbnail.
 static const int kVerticalPadding = 10;
 
-TabOverviewCell::TabOverviewCell() {
+TabOverviewCell::TabOverviewCell() : configured_thumbnail_(false) {
   title_label_ = new views::Label();
   title_label_->SetHorizontalAlignment(views::Label::ALIGN_LEFT);
 
@@ -69,6 +69,7 @@ void TabOverviewCell::SetThumbnail(const SkBitmap& thumbnail) {
   // input bitmap isn't guaranteed to have any specific resolution.
   thumbnail_view_->SetImage(skia::ImageOperations::DownsampleByTwoUntilSize(
       thumbnail, kThumbnailWidth, kThumbnailHeight));
+  configured_thumbnail_ = true;
 }
 
 void TabOverviewCell::SetTitle(const string16& title) {
diff --git a/chrome/browser/views/tabs/tab_overview_cell.h b/chrome/browser/views/tabs/tab_overview_cell.h
index 9411cec..08c0055 100644
--- a/chrome/browser/views/tabs/tab_overview_cell.h
+++ b/chrome/browser/views/tabs/tab_overview_cell.h
@@ -35,6 +35,10 @@ class TabOverviewCell : public views::View {
   // the thumbnail.
   bool IsPointInThumbnail(const gfx::Point& point);
 
+  // Has the thumbnail been configured? This is true after SetThumbnail
+  // is invoked.
+  bool configured_thumbnail() const { return configured_thumbnail_; }
+
   // View overrides.
   virtual gfx::Size GetPreferredSize();
 
@@ -46,6 +50,8 @@ class TabOverviewCell : public views::View {
   // Specific preferred size. See set_preferred_size() for details.
   gfx::Size preferred_size_;
 
+  bool configured_thumbnail_;
+
   DISALLOW_COPY_AND_ASSIGN(TabOverviewCell);
 };
 
diff --git a/chrome/browser/views/tabs/tab_overview_controller.cc b/chrome/browser/views/tabs/tab_overview_controller.cc
index fd4e403..f4027b3 100644
--- a/chrome/browser/views/tabs/tab_overview_controller.cc
+++ b/chrome/browser/views/tabs/tab_overview_controller.cc
@@ -38,7 +38,8 @@ TabOverviewController::TabOverviewController(
       shown_(false),
       horizontal_center_(0),
       change_window_bounds_on_animate_(false),
-      mutating_grid_(false) {
+      mutating_grid_(false),
+      show_thumbnails_(false) {
   grid_ = new TabOverviewGrid(this);
 
   // Determine the max size for the overview.
@@ -108,6 +109,9 @@ void TabOverviewController::Show() {
   shown_ = true;
   DCHECK(model());  // The model needs to be set before showing.
   host_->Show();
+  delay_timer_.Start(
+      base::TimeDelta::FromMilliseconds(350), this,
+      &TabOverviewController::StartConfiguring);
 }
 
 void TabOverviewController::ConfigureCell(TabOverviewCell* cell,
@@ -116,14 +120,21 @@ void TabOverviewController::ConfigureCell(TabOverviewCell* cell,
     cell->SetTitle(contents->GetTitle());
     cell->SetFavIcon(contents->GetFavIcon());
 
-    ThumbnailGenerator* generator = g_browser_process->GetThumbnailGenerator();
-    cell->SetThumbnail(
-        generator->GetThumbnailForRenderer(contents->render_view_host()));
-
+    if (show_thumbnails_) {
+      ThumbnailGenerator* generator =
+          g_browser_process->GetThumbnailGenerator();
+      cell->SetThumbnail(
+          generator->GetThumbnailForRenderer(contents->render_view_host()));
+    }
     cell->SchedulePaint();
   } else {
     // Need to figure out under what circumstances this is null and deal.
     NOTIMPLEMENTED();
+
+    // Make sure we set the thumbnail, otherwise configured_thumbnail
+    // remains false and ConfigureNextUnconfiguredCell would get stuck.
+    if (show_thumbnails_)
+      cell->SetThumbnail(SkBitmap());
   }
 }
 
@@ -309,3 +320,21 @@ gfx::Rect TabOverviewController::CalculateHostBounds() {
                    kWindowToOverviewPadding - max_height, max_width,
                    max_height);
 }
+
+void TabOverviewController::StartConfiguring() {
+  show_thumbnails_ = true;
+  configure_timer_.Start(
+      base::TimeDelta::FromMilliseconds(10), this,
+      &TabOverviewController::ConfigureNextUnconfiguredCell);
+}
+
+void TabOverviewController::ConfigureNextUnconfiguredCell() {
+  for (int i = 0; i < grid_->GetChildViewCount(); ++i) {
+    TabOverviewCell* cell = grid_->GetTabOverviewCellAt(i);
+    if (!cell->configured_thumbnail()) {
+      ConfigureCell(cell, i);
+      return;
+    }
+  }
+  configure_timer_.Stop();
+}
diff --git a/chrome/browser/views/tabs/tab_overview_controller.h b/chrome/browser/views/tabs/tab_overview_controller.h
index 494f01c..15b13f5 100644
--- a/chrome/browser/views/tabs/tab_overview_controller.h
+++ b/chrome/browser/views/tabs/tab_overview_controller.h
@@ -7,6 +7,7 @@
 
 #include "base/gfx/rect.h"
 #include "base/scoped_ptr.h"
+#include "base/timer.h"
 #include "chrome/browser/tabs/tab_strip_model.h"
 
 class Animation;
@@ -28,6 +29,13 @@ class Widget;
 // size of the host window is created at the largest possible size the
 // window can be and the bounds of the container are changed during the
 // animation.
+//
+// As obtaining and setting thumbnails is expensive we delay setting the
+// thumbnail. The delay is controlled by delay_timer_. Once the timer fires
+// another timer is started (configure_timer_). This timer invokes
+// ConfigureNextUnconfiguredCell, which obtains and sets the thumbnail of
+// the next uncofigured cell. ConfigureNextUnconfiguredCell only configures
+// one cell at a time.
 class TabOverviewController : public TabStripModelObserver {
  public:
   // Creates a TabOverviewController that will be shown on the monitor
@@ -110,6 +118,14 @@ class TabOverviewController : public TabStripModelObserver {
   // See comment above class description for more details.
   gfx::Rect CalculateHostBounds();
 
+  // Invoked by delay_timer_. Sets show_thumbnails_ to true and starts
+  // configure_timer_.
+  void StartConfiguring();
+
+  // Finds the first cell with no thumbnail and invokes ConfigureCell for
+  // it. If all the thumnbails have been set configure_timer_ is stopped.
+  void ConfigureNextUnconfiguredCell();
+
   // The widget showing the view.
   views::Widget* host_;
 
@@ -152,6 +168,16 @@ class TabOverviewController : public TabStripModelObserver {
   // bounds when we're responsible for the mutation.
   bool mutating_grid_;
 
+  // Should we set the thumbnails? This is initially false, then set to true
+  // by StartConfiguring.
+  bool show_thumbnails_;
+
+  // See description above class for details.
+  base::OneShotTimer<TabOverviewController> delay_timer_;
+
+  // See description above class for details.
+  base::RepeatingTimer<TabOverviewController> configure_timer_;
+
   DISALLOW_COPY_AND_ASSIGN(TabOverviewController);
 };
 
diff --git a/chrome/browser/views/tabs/tab_overview_message_listener.cc b/chrome/browser/views/tabs/tab_overview_message_listener.cc
index 63dff1f..0f3b1f3 100644
--- a/chrome/browser/views/tabs/tab_overview_message_listener.cc
+++ b/chrome/browser/views/tabs/tab_overview_message_listener.cc
@@ -60,6 +60,8 @@ void TabOverviewMessageListener::ProcessMessage(
     }
 
     case TabOverviewTypes::Message::CHROME_NOTIFY_LAYOUT_MODE: {
+      // TODO: enable this once we have type.
+#if 0
       if (message.param(0) == 0) {
         new_browser_window_.reset(NULL);
       } else if (BrowserList::size() > 0) {
@@ -67,6 +69,7 @@ void TabOverviewMessageListener::ProcessMessage(
         new_browser_window_.reset(
             new NewBrowserWindowWidget(browser->profile()));
       }
+#endif
       break;
     }