Separate ResizeHelper from RenderWidgetHelper

content/browser/renderer_host/render_widget_helper.h

 // 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.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HELPER_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HELPER_H_
 
-#include <deque>
 #include <map>
 
 #include "base/atomic_sequence_num.h"
 #include "base/containers/hash_tables.h"
 #include "base/memory/ref_counted.h"
 #include "base/process/process.h"
-#include "base/synchronization/lock.h"
-#include "base/synchronization/waitable_event.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/content_browser_client.h"
 #include "content/public/browser/global_request_id.h"
 #include "content/public/common/window_container_type.h"
 #include "third_party/WebKit/public/web/WebPopupType.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/surface/transport_dib.h"
 
 namespace IPC {
 class Message;
@@ skipping 11 matching lines @@
 class GpuProcessHost;
 class ResourceDispatcherHostImpl;
 class SessionStorageNamespace;
 
 // 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.  In response to the Resize message,
-//   the RenderWidget generates a new BackingStore and sends an UpdateRect
-//   message (or BuffersSwapped via the GPU process in the case of accelerated
-//   compositing), and it sets the IS_RESIZE_ACK flag in the UpdateRect message
-//   to true.  In the accelerated case, an UpdateRect is still sent from the
-//   renderer to the browser with acks and plugin moves even though the GPU
-//   BackingStore was sent earlier in the BuffersSwapped message. "BackingStore
-//   message" is used throughout this code and documentation to mean either a
-//   software UpdateRect or GPU BuffersSwapped message.
-//
-//   Back in the browser process, when the RenderProcessHost's MessageFilter
-//   sees an UpdateRect message (or when the GpuProcessHost sees a
-//   BuffersSwapped message), it directs it to the RenderWidgetHelper by calling
-//   the DidReceiveBackingStoreMsg method. That method stores the data for the
-//   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 WaitForBackingStoreMsg to check if there is
-//   already a resulting BackingStore 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 BackingStore
 //   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 be without a backingstore.  (Restoring
 //   a RenderWidgetHost results in a WasShown message being sent to the
 //   RenderWidget, which triggers a full BackingStore message.)  This can lead
 //   to an observed rendering glitch as the WebContentsImpl will just have to
 //   fill white overtop the RenderWidgetHost until the RenderWidgetHost
 //   receives a BackingStore message to refresh its backingstore.
 //
 //   To avoid this 'white flash', the RenderWidgetHost again makes use of the
 //   RenderWidgetHelper's WaitForBackingStoreMsg method.  When the
 //   RenderWidgetHost's GetBackingStore method is called, it will call
 //   WaitForBackingStoreMsg if it has no backingstore.
 //
 // TRANSPORT DIB CREATION
 //
 //   On some platforms (currently the Mac) the renderer cannot create transport
 //   DIBs because of sandbox limitations. Thus, it has to make synchronous IPCs
 //   to the browser for them. Since these requests are synchronous, they cannot
 //   terminate on the UI thread. Thus, in this case, this object performs the
 //   allocation and maintains the set of allocated transport DIBs which the
 //   renderers can refer to.
 //
+
 class RenderWidgetHelper
     : public base::RefCountedThreadSafe<RenderWidgetHelper,
                                         BrowserThread::DeleteOnIOThread> {
  public:
   RenderWidgetHelper();
 
   void Init(int render_process_id,
             ResourceDispatcherHostImpl* resource_dispatcher_host);
 
   // Gets the next available routing id.  This is thread safe.
   int GetNextRoutingID();
 
   // IO THREAD ONLY -----------------------------------------------------------
 
   // Lookup the RenderWidgetHelper from the render_process_host_id. Returns NULL
   // if not found. NOTE: The raw pointer is for temporary use only. To retain,
   // store in a scoped_refptr.
   static RenderWidgetHelper* FromProcessHostID(int render_process_host_id);
 
   // UI THREAD ONLY -----------------------------------------------------------
 
   // These four functions provide the backend implementation of the
   // corresponding functions in RenderProcessHost. See those declarations
   // for documentation.
   void ResumeDeferredNavigation(const GlobalRequestID& request_id);
   void ResumeResponseDeferredAtStart(const GlobalRequestID& request_id);
-  bool WaitForBackingStoreMsg(int render_widget_id,
-                              const base::TimeDelta& max_delay,
-                              IPC::Message* msg);
+
   // Called to resume the requests for a view after it's ready. The view was
   // created by CreateNewWindow which initially blocked the requests.
   void ResumeRequestsForView(int route_id);
 
+#if defined(OS_MACOSX)
+  static void OnNativeSurfaceBuffersSwappedOnUIThread(
+      const GpuHostMsg_AcceleratedSurfaceBuffersSwapped_Params& params);
+#endif
+
   // IO THREAD ONLY -----------------------------------------------------------
 
-  // Called on the IO thread when a BackingStore message is received.
-  void DidReceiveBackingStoreMsg(const IPC::Message& msg);
-
   void CreateNewWindow(
       const ViewHostMsg_CreateWindow_Params& params,
       bool no_javascript_access,
       base::ProcessHandle render_process,
       int* route_id,
       int* main_frame_route_id,
       int* surface_id,
       SessionStorageNamespace* session_storage_namespace);
   void CreateNewWidget(int opener_id,
                        blink::WebPopupType popup_type,
                        int* route_id,
                        int* surface_id);
   void CreateNewFullscreenWidget(int opener_id, int* route_id, int* surface_id);
 
 #if defined(OS_POSIX)
   // Called on the IO thread to handle the allocation of a TransportDIB.  If
   // |cache_in_browser| is |true|, then a copy of the shmem is kept by the
   // browser, and it is the caller's repsonsibility to call
   // FreeTransportDIB().  In all cases, the caller is responsible for deleting
   // the resulting TransportDIB.
   void AllocTransportDIB(uint32 size,
                          bool cache_in_browser,
                          TransportDIB::Handle* result);
 
   // Called on the IO thread to handle the freeing of a transport DIB
   void FreeTransportDIB(TransportDIB::Id dib_id);
 #endif
 
-#if defined(OS_MACOSX)
-  static void OnNativeSurfaceBuffersSwappedOnIOThread(
-      GpuProcessHost* gpu_process_host,
-      const GpuHostMsg_AcceleratedSurfaceBuffersSwapped_Params& params);
-#endif
-
  private:
-  // A class used to proxy a paint message.  PaintMsgProxy objects are created
-  // on the IO thread and destroyed on the UI thread.
-  class BackingStoreMsgProxy;
-  friend class BackingStoreMsgProxy;
   friend class base::RefCountedThreadSafe<RenderWidgetHelper>;
   friend struct BrowserThread::DeleteOnThread<BrowserThread::IO>;
   friend class base::DeleteHelper<RenderWidgetHelper>;
 
-  typedef std::deque<BackingStoreMsgProxy*> BackingStoreMsgProxyQueue;
-  // Map from render_widget_id to a queue of live PaintMsgProxy instances.
-  typedef base::hash_map<int, BackingStoreMsgProxyQueue >
-      BackingStoreMsgProxyMap;
-
   ~RenderWidgetHelper();
 
-  // Called on the UI thread to discard a paint message.
-  void OnDiscardBackingStoreMsg(BackingStoreMsgProxy* proxy);
-
-  // Called on the UI thread to dispatch a paint message if necessary.
-  void OnDispatchBackingStoreMsg(BackingStoreMsgProxy* proxy);
-
   // Called on the UI thread to finish creating a window.
   void OnCreateWindowOnUI(
       const ViewHostMsg_CreateWindow_Params& params,
       int route_id,
       int main_frame_route_id,
       SessionStorageNamespace* session_storage_namespace);
 
   // Called on the IO thread after a window was created on the UI thread.
   void OnResumeRequestsForView(int route_id);
 
@@ skipping 16 matching lines @@
 #if defined(OS_POSIX)
   // Called on destruction to release all allocated transport DIBs
   void ClearAllocatedDIBs();
 
   // On POSIX we keep file descriptors to all the allocated DIBs around until
   // the renderer frees them.
   base::Lock allocated_dibs_lock_;
   std::map<TransportDIB::Id, int> allocated_dibs_;
 #endif
 
-  // A map of live paint messages.  Must hold pending_paints_lock_ to access.
-  // The BackingStoreMsgProxy objects are not owned by this map. (See
-  // BackingStoreMsgProxy for details about how the lifetime of instances are
-  // managed.)
-  BackingStoreMsgProxyMap pending_paints_;
-  base::Lock pending_paints_lock_;
-
   int render_process_id_;
 
-  // Event used to implement WaitForBackingStoreMsg.
-  base::WaitableEvent event_;
-
   // The next routing id to use.
   base::AtomicSequenceNumber next_routing_id_;
 
   ResourceDispatcherHostImpl* resource_dispatcher_host_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHelper);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HELPER_H_