Adds kind-of-live thumbnail generation for a potential tab switcher.

chrome/browser/renderer_host/render_widget_host.cc

 // Copyright (c) 2009 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/renderer_host/render_widget_host.h"
 
 #include "base/histogram.h"
 #include "base/message_loop.h"
 #include "base/keyboard_codes.h"
 #include "chrome/browser/renderer_host/backing_store.h"
 #include "chrome/browser/renderer_host/backing_store_manager.h"
 #include "chrome/browser/renderer_host/render_process_host.h"
 #include "chrome/browser/renderer_host/render_widget_helper.h"
+#include "chrome/browser/renderer_host/render_widget_host_painting_observer.h"
 #include "chrome/browser/renderer_host/render_widget_host_view.h"
 #include "chrome/common/notification_service.h"
 #include "chrome/common/render_messages.h"
 #include "views/view.h"
 #include "webkit/glue/webcursor.h"
 #include "webkit/glue/webtextdirection.h"
 
 #if defined(OS_WIN)
 #include "base/gfx/gdi_util.h"
 #include "chrome/app/chrome_dll_resource.h"
@@ skipping 18 matching lines @@
 static const int kHungRendererDelayMs = 20000;
 
 ///////////////////////////////////////////////////////////////////////////////
 // RenderWidgetHost
 
 RenderWidgetHost::RenderWidgetHost(RenderProcessHost* process,
                                    int routing_id)
     : renderer_initialized_(false),
       view_(NULL),
       process_(process),
+      painting_observer_(NULL),
       routing_id_(routing_id),
       is_loading_(false),
       is_hidden_(false),
       repaint_ack_pending_(false),
       resize_ack_pending_(false),
       mouse_move_pending_(false),
       needs_repainting_on_restore_(false),
       is_unresponsive_(false),
       in_get_backing_store_(false),
       view_being_painted_(false),
@@ skipping 73 matching lines @@
   // reduce its resource utilization.
   Send(new ViewMsg_WasHidden(routing_id_));
 
   // TODO(darin): what about constrained windows?  it doesn't look like they
   // see a message when their parent is hidden.  maybe there is something more
   // generic we can do at the TabContents API level instead of relying on
   // Windows messages.
 
   // Tell the RenderProcessHost we were hidden.
   process_->WidgetHidden();
+
+  bool is_visible = false;
+  NotificationService::current()->Notify(
+      NotificationType::RENDER_WIDGET_VISIBILITY_CHANGED,
+      Source<RenderWidgetHost>(this),
+      Details<bool>(&is_visible));
 }
 
 void RenderWidgetHost::WasRestored() {
   // When we create the widget, it is created as *not* hidden.
   if (!is_hidden_)
     return;
   is_hidden_ = false;
 
   BackingStore* backing_store = BackingStoreManager::Lookup(this);
   // If we already have a backing store for this widget, then we don't need to
   // repaint on restore _unless_ we know that our backing store is invalid.
   bool needs_repainting;
   if (needs_repainting_on_restore_ || !backing_store) {
     needs_repainting = true;
     needs_repainting_on_restore_ = false;
   } else {
     needs_repainting = false;
   }
   Send(new ViewMsg_WasRestored(routing_id_, needs_repainting));
 
   process_->WidgetRestored();
+
+  bool is_visible = true;
+  NotificationService::current()->Notify(
+      NotificationType::RENDER_WIDGET_VISIBILITY_CHANGED,
+      Source<RenderWidgetHost>(this),
+      Details<bool>(&is_visible));
 }
 
 void RenderWidgetHost::WasResized() {
   if (resize_ack_pending_ || !process_->channel() || !view_ ||
       !renderer_initialized_) {
     return;
   }
 
   gfx::Rect view_bounds = view_->GetViewBounds();
   gfx::Size new_size(view_bounds.width(), view_bounds.height());
@@ skipping 34 matching lines @@
   view_ = NULL;
 }
 
 void RenderWidgetHost::SetIsLoading(bool is_loading) {
   is_loading_ = is_loading;
   if (!view_)
     return;
   view_->SetIsLoading(is_loading);
 }
 
-BackingStore* RenderWidgetHost::GetBackingStore() {
+BackingStore* RenderWidgetHost::GetBackingStore(bool force_create) {
   // We should not be asked to paint while we are hidden.  If we are hidden,
-  // then it means that our consumer failed to call WasRestored.
-  DCHECK(!is_hidden_) << "GetBackingStore called while hidden!";
+  // then it means that our consumer failed to call WasRestored. If we're not
+  // force creating the backing store, it's OK since we can feel free to give
+  // out our cached one if we have it.
+  DCHECK(!is_hidden_ || !force_create) <<
+      "GetBackingStore called while hidden!";
 
   // We should never be called recursively; this can theoretically lead to
   // infinite recursion and almost certainly leads to lower performance.
   DCHECK(!in_get_backing_store_) << "GetBackingStore called recursively!";
   in_get_backing_store_ = true;
 
   // We might have a cached backing store that we can reuse!
   BackingStore* backing_store =
       BackingStoreManager::GetBackingStore(this, current_size_);
+  if (!force_create) {
+    in_get_backing_store_ = false;
+    return backing_store;
+  }
+
   // If we fail to find a backing store in the cache, send out a request
   // to the renderer to paint the view if required.
   if (!backing_store && !repaint_ack_pending_ && !resize_ack_pending_ &&
       !view_being_painted_) {
     repaint_start_time_ = TimeTicks::Now();
     repaint_ack_pending_ = true;
     Send(new ViewMsg_Repaint(routing_id_, current_size_));
   }
 
   // When we have asked the RenderWidget to resize, and we are still waiting on
   // a response, block for a little while to see if we can't get a response
   // before returning the old (incorrectly sized) backing store.
   if (resize_ack_pending_ || !backing_store) {
     IPC::Message msg;
     TimeDelta max_delay = TimeDelta::FromMilliseconds(kPaintMsgTimeoutMS);
     if (process_->WaitForPaintMsg(routing_id_, max_delay, &msg)) {
       ViewHostMsg_PaintRect::Dispatch(
           &msg, this, &RenderWidgetHost::OnMsgPaintRect);
       backing_store = BackingStoreManager::GetBackingStore(this, current_size_);
     }
   }
 
   in_get_backing_store_ = false;
   return backing_store;
 }
 
 BackingStore* RenderWidgetHost::AllocBackingStore(const gfx::Size& size) {
   if (!view_)
     return NULL;
-
   return view_->AllocBackingStore(size);
 }
 
 void RenderWidgetHost::StartHangMonitorTimeout(TimeDelta delay) {
   time_when_considered_hung_ = Time::Now() + delay;
 
   // If we already have a timer that will expire at or before the given delay,
   // then we have nothing more to do now.
   if (hung_renderer_timer_.IsRunning() &&
       hung_renderer_timer_.GetCurrentDelay() <= delay)
@@ skipping 269 matching lines @@
 
   // If we got a resize ack, then perhaps we have another resize to send?
   if (is_resize_ack && view_) {
     gfx::Rect view_bounds = view_->GetViewBounds();
     if (current_size_.width() != view_bounds.width() ||
         current_size_.height() != view_bounds.height()) {
       WasResized();
     }
   }
 
+  if (painting_observer_)
+    painting_observer_->WidgetDidUpdateBackingStore(this);
+
   // Log the time delta for processing a paint message.
   TimeDelta delta = TimeTicks::Now() - paint_start;
   UMA_HISTOGRAM_TIMES("MPArch.RWH_OnMsgPaintRect", delta);
 }
 
 void RenderWidgetHost::OnMsgScrollRect(
     const ViewHostMsg_ScrollRect_Params& params) {
   TimeTicks scroll_start = TimeTicks::Now();
 
   DCHECK(!params.view_size.IsEmpty());
@@ skipping 26 matching lines @@
     return;
 
   // Paint the view. Watch out: it might be destroyed already.
   if (view_) {
     view_being_painted_ = true;
     view_->MovePluginWindows(params.plugin_window_moves);
     view_->DidScrollRect(params.clip_rect, params.dx, params.dy);
     view_being_painted_ = false;
   }
 
+  if (painting_observer_)
+    painting_observer_->WidgetDidUpdateBackingStore(this);
+
   // Log the time delta for processing a scroll message.
   TimeDelta delta = TimeTicks::Now() - scroll_start;
   UMA_HISTOGRAM_TIMES("MPArch.RWH_OnMsgScrollRect", delta);
 }
 
 void RenderWidgetHost::OnMsgInputEventAck(const IPC::Message& message) {
   // Log the time delta for processing an input event.
   TimeDelta delta = TimeTicks::Now() - input_event_start_time_;
   UMA_HISTOGRAM_TIMES("MPArch.RWH_InputEventDelta", delta);
 
@@ skipping 128 matching lines @@
 
   // TODO(darin): do we need to do something else if our backing store is not
   // the same size as the advertised view?  maybe we just assume there is a
   // full paint on its way?
   BackingStore* backing_store = BackingStoreManager::Lookup(this);
   if (!backing_store || (backing_store->size() != view_size))
     return;
   backing_store->ScrollRect(process_->process().handle(), bitmap, bitmap_rect,
                             dx, dy, clip_rect, view_size);
 }