Move files out of browser and into either renderer_host or tab_contents.

This also fixes a crash in the web contents unit test in a commented-out test and re-enable it.
Review URL: http://codereview.chromium.org/18504

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@8470 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 159 insertions, 0 deletions

diff --git a/chrome/browser/renderer_host/render_widget_helper.h b/chrome/browser/renderer_host/render_widget_helper.h
new file mode 100644
index 0000000..aca3644
--- /dev/null
+++ b/chrome/browser/renderer_host/render_widget_helper.h
@@ -0,0 +1,159 @@
+
+// Copyright (c) 2006-2008 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.
+
+#ifndef CHROME_BROWSER_RENDEDER_HOST_RENDER_WIDGET_HELPER_H_
+#define CHROME_BROWSER_RENDEDER_HOST_RENDER_WIDGET_HELPER_H_
+
+#include "base/atomic_sequence_num.h"
+#include "base/hash_tables.h"
+#include "base/ref_counted.h"
+#include "base/lock.h"
+
+namespace IPC {
+class Message;
+}
+
+namespace base {
+class TimeDelta;
+}
+
+class MessageLoop;
+class ResourceDispatcherHost;
+
+// Instantiated per RenderProcessHost to provide various optimizations on
+// behalf of a RenderWidgetHost.  This class bridges between the IO thread
+// where the RenderProcessHost's MessageFilter lives and the UI thread where
+// the RenderWidgetHost lives.
+//
+//
+// OPTIMIZED RESIZE
+//
+//   RenderWidgetHelper is used to implement optimized resize.  When the
+//   RenderWidgetHost is resized, it sends a Resize message to its RenderWidget
+//   counterpart in the renderer process.  The RenderWidget generates a
+//   PaintRect message in response to the Resize message, and it sets the
+//   IS_RESIZE_ACK flag in the PaintRect message to true.
+//
+//   Back in the browser process, when the RenderProcessHost's MessageFilter
+//   sees a PaintRect message, it directs it to the RenderWidgetHelper by
+//   calling the DidReceivePaintMsg method.  That method stores the data for
+//   the PaintRect message in a map, where it can be directly accessed by the
+//   RenderWidgetHost on the UI thread during a call to RenderWidgetHost's
+//   GetBackingStore method.
+//
+//   When the RenderWidgetHost's GetBackingStore method is called, it first
+//   checks to see if it is waiting for a resize ack.  If it is, then it calls
+//   the RenderWidgetHelper's WaitForPaintMsg to check if there is already a
+//   resulting PaintRect message (or to wait a short amount of time for one to
+//   arrive).  The main goal of this mechanism is to short-cut the usual way in
+//   which IPC messages are proxied over to the UI thread via InvokeLater.
+//   This approach is necessary since window resize is followed up immediately
+//   by a request to repaint the window.
+//
+//
+// OPTIMIZED TAB SWITCHING
+//
+//   When a RenderWidgetHost is in a background tab, it is flagged as hidden.
+//   This causes the corresponding RenderWidget to stop sending PaintRect
+//   messages. The RenderWidgetHost also discards its backingstore when it is
+//   hidden, which helps free up memory.  As a result, when a RenderWidgetHost
+//   is restored, it can be momentarily without a backingstore.  (Restoring a
+//   RenderWidgetHost results in a WasRestored message being sent to the
+//   RenderWidget, which triggers a full PaintRect message.)  This can lead to
+//   an observed rendering glitch as the WebContents will just have to fill
+//   white overtop the RenderWidgetHost until the RenderWidgetHost receives a
+//   PaintRect message to refresh its backingstore.
+//
+//   To avoid this 'white flash', the RenderWidgetHost again makes use of the
+//   RenderWidgetHelper's WaitForPaintMsg method.  When the RenderWidgetHost's
+//   GetBackingStore method is called, it will call WaitForPaintMsg if it has
+//   no backingstore.
+//
+class RenderWidgetHelper :
+    public base::RefCountedThreadSafe<RenderWidgetHelper> {
+ public:
+  RenderWidgetHelper(int render_process_id);
+  ~RenderWidgetHelper();
+
+  // Gets the next available routing id.  This is thread safe.
+  int GetNextRoutingID();
+
+  // Sets whether popup blocking is enabled or not.
+  void set_block_popups(bool block) { block_popups_ = block; }
+
+
+  // UI THREAD ONLY -----------------------------------------------------------
+
+  // These three functions provide the backend implementation of the
+  // corresponding functions in RenderProcessHost. See those declarations
+  // for documentation.
+  void CancelResourceRequests(int render_widget_id);
+  void CrossSiteClosePageACK(int new_render_process_host_id,
+                             int new_request_id);
+  bool WaitForPaintMsg(int render_widget_id,
+                       const base::TimeDelta& max_delay,
+                       IPC::Message* msg);
+
+
+  // IO THREAD ONLY -----------------------------------------------------------
+
+  // Called on the IO thread when a PaintRect message is received.
+  void DidReceivePaintMsg(const IPC::Message& msg);
+
+  MessageLoop* ui_loop() { return ui_loop_; }
+
+  void CreateNewWindow(int opener_id, bool user_gesture, int* route_id,
+                       HANDLE* modal_dialog_event, HANDLE render_process);
+  void CreateNewWidget(int opener_id, bool activatable, int* route_id);
+
+ private:
+  // A class used to proxy a paint message.  PaintMsgProxy objects are created
+  // on the IO thread and destroyed on the UI thread.
+  class PaintMsgProxy;
+  friend class PaintMsgProxy;
+
+  // Map from render_widget_id to live PaintMsgProxy instance.
+  typedef base::hash_map<int, PaintMsgProxy*> PaintMsgProxyMap;
+
+  // Called on the UI thread to discard a paint message.
+  void OnDiscardPaintMsg(PaintMsgProxy* proxy);
+
+  // Called on the UI thread to dispatch a paint message if necessary.
+  void OnDispatchPaintMsg(PaintMsgProxy* proxy);
+
+  // Called on the UI thread to send a message to the RenderProcessHost.
+  void OnSimulateReceivedMessage(const IPC::Message& message);
+
+  // Called on the IO thread to cancel resource requests for the render widget.
+  void OnCancelResourceRequests(ResourceDispatcherHost* dispatcher,
+                                int render_widget_id);
+
+  // Called on the IO thread to resume a cross-site response.
+  void OnCrossSiteClosePageACK(ResourceDispatcherHost* dispatcher,
+                               int new_render_process_host_id,
+                               int new_request_id);
+
+  // A map of live paint messages.  Must hold pending_paints_lock_ to access.
+  // The PaintMsgProxy objects are not owned by this map.  (See PaintMsgProxy
+  // for details about how the lifetime of instances are managed.)
+  PaintMsgProxyMap pending_paints_;
+  Lock pending_paints_lock_;
+
+  int render_process_id_;
+  MessageLoop* ui_loop_;
+
+  // Event used to implement WaitForPaintMsg.
+  HANDLE event_;
+
+  // The next routing id to use.
+  base::AtomicSequenceNumber next_routing_id_;
+
+  // Whether popup blocking is enabled or not.
+  bool block_popups_;
+
+  DISALLOW_COPY_AND_ASSIGN(RenderWidgetHelper);
+};
+
+#endif  // CHROME_BROWSER_RENDEDER_HOST_RENDER_WIDGET_HELPER_H_