content/browser/renderer_host/render_widget_helper.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HELPER_H_
   6 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HELPER_H_
   7
   8 #include <map>
   9
  10 #include "base/atomic_sequence_num.h"
  11 #include "base/containers/hash_tables.h"
  12 #include "base/memory/ref_counted.h"
  13 #include "base/process/process.h"
  14 #include "content/public/browser/browser_thread.h"
  15 #include "content/public/browser/content_browser_client.h"
  16 #include "content/public/browser/global_request_id.h"
  17 #include "content/public/common/window_container_type.h"
  18 #include "third_party/WebKit/public/web/WebPopupType.h"
  19 #include "ui/gfx/native_widget_types.h"
  20
  21 namespace IPC {
  22 class Message;
  23 }
  24
  25 namespace base {
  26 class TimeDelta;
  27 }
  28
  29 struct ViewHostMsg_CreateWindow_Params;
  30 struct ViewMsg_SwapOut_Params;
  31
  32 namespace content {
  33 class GpuProcessHost;
  34 class ResourceDispatcherHostImpl;
  35 class SessionStorageNamespace;
  36
  37 // Instantiated per RenderProcessHost to provide various optimizations on
  38 // behalf of a RenderWidgetHost.  This class bridges between the IO thread
  39 // where the RenderProcessHost's MessageFilter lives and the UI thread where
  40 // the RenderWidgetHost lives.
  41 //
  42 //
  43 // OPTIMIZED TAB SWITCHING
  44 //
  45 //   When a RenderWidgetHost is in a background tab, it is flagged as hidden.
  46 //   This causes the corresponding RenderWidget to stop sending BackingStore
  47 //   messages. The RenderWidgetHost also discards its backingstore when it is
  48 //   hidden, which helps free up memory.  As a result, when a RenderWidgetHost
  49 //   is restored, it can be momentarily be without a backingstore.  (Restoring
  50 //   a RenderWidgetHost results in a WasShown message being sent to the
  51 //   RenderWidget, which triggers a full BackingStore message.)  This can lead
  52 //   to an observed rendering glitch as the WebContentsImpl will just have to
  53 //   fill white overtop the RenderWidgetHost until the RenderWidgetHost
  54 //   receives a BackingStore message to refresh its backingstore.
  55 //
  56 //   To avoid this 'white flash', the RenderWidgetHost again makes use of the
  57 //   RenderWidgetHelper's WaitForBackingStoreMsg method.  When the
  58 //   RenderWidgetHost's GetBackingStore method is called, it will call
  59 //   WaitForBackingStoreMsg if it has no backingstore.
  60 //
  61 // TRANSPORT DIB CREATION
  62 //
  63 //   On some platforms (currently the Mac) the renderer cannot create transport
  64 //   DIBs because of sandbox limitations. Thus, it has to make synchronous IPCs
  65 //   to the browser for them. Since these requests are synchronous, they cannot
  66 //   terminate on the UI thread. Thus, in this case, this object performs the
  67 //   allocation and maintains the set of allocated transport DIBs which the
  68 //   renderers can refer to.
  69 //
  70
  71 class RenderWidgetHelper
  72     : public base::RefCountedThreadSafe<RenderWidgetHelper,
  73                                         BrowserThread::DeleteOnIOThread> {
  74  public:
  75   RenderWidgetHelper();
  76
  77   void Init(int render_process_id,
  78             ResourceDispatcherHostImpl* resource_dispatcher_host);
  79
  80   // Gets the next available routing id.  This is thread safe.
  81   int GetNextRoutingID();
  82
  83   // IO THREAD ONLY -----------------------------------------------------------
  84
  85   // Lookup the RenderWidgetHelper from the render_process_host_id. Returns NULL
  86   // if not found. NOTE: The raw pointer is for temporary use only. To retain,
  87   // store in a scoped_refptr.
  88   static RenderWidgetHelper* FromProcessHostID(int render_process_host_id);
  89
  90   // UI THREAD ONLY -----------------------------------------------------------
  91
  92   // These two functions provide the backend implementation of the
  93   // corresponding functions in RenderProcessHost. See those declarations
  94   // for documentation.
  95   void ResumeDeferredNavigation(const GlobalRequestID& request_id);
  96
  97   // Called to resume the requests for a view after it's ready. The view was
  98   // created by CreateNewWindow which initially blocked the requests.
  99   void ResumeRequestsForView(int route_id);
 100
 101   // IO THREAD ONLY -----------------------------------------------------------
 102
 103   void CreateNewWindow(
 104       const ViewHostMsg_CreateWindow_Params& params,
 105       bool no_javascript_access,
 106       base::ProcessHandle render_process,
 107       int* route_id,
 108       int* main_frame_route_id,
 109       int* surface_id,
 110       SessionStorageNamespace* session_storage_namespace);
 111   void CreateNewWidget(int opener_id,
 112                        blink::WebPopupType popup_type,
 113                        int* route_id,
 114                        int* surface_id);
 115   void CreateNewFullscreenWidget(int opener_id, int* route_id, int* surface_id);
 116
 117  private:
 118   friend class base::RefCountedThreadSafe<RenderWidgetHelper>;
 119   friend struct BrowserThread::DeleteOnThread<BrowserThread::IO>;
 120   friend class base::DeleteHelper<RenderWidgetHelper>;
 121
 122   ~RenderWidgetHelper();
 123
 124   // Called on the UI thread to finish creating a window.
 125   void OnCreateWindowOnUI(
 126       const ViewHostMsg_CreateWindow_Params& params,
 127       int route_id,
 128       int main_frame_route_id,
 129       SessionStorageNamespace* session_storage_namespace);
 130
 131   // Called on the IO thread after a window was created on the UI thread.
 132   void OnResumeRequestsForView(int route_id);
 133
 134   // Called on the UI thread to finish creating a widget.
 135   void OnCreateWidgetOnUI(int opener_id,
 136                           int route_id,
 137                           blink::WebPopupType popup_type);
 138
 139   // Called on the UI thread to create a fullscreen widget.
 140   void OnCreateFullscreenWidgetOnUI(int opener_id, int route_id);
 141
 142   // Called on the IO thread to resume a paused navigation in the network
 143   // stack without transferring it to a new renderer process.
 144   void OnResumeDeferredNavigation(const GlobalRequestID& request_id);
 145
 146   // Called on the IO thread to resume a navigation paused immediately after
 147   // receiving response headers.
 148   void OnResumeResponseDeferredAtStart(const GlobalRequestID& request_id);
 149
 150   int render_process_id_;
 151
 152   // The next routing id to use.
 153   base::AtomicSequenceNumber next_routing_id_;
 154
 155   ResourceDispatcherHostImpl* resource_dispatcher_host_;
 156
 157   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHelper);
 158 };
 159
 160 }  // namespace content
 161
 162 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HELPER_H_