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// 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 <stdint.h>
#include <map>
#include "base/atomic_sequence_num.h"
#include "base/containers/hash_tables.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/process/process.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"
namespace IPC {
class Message;
}
namespace base {
class TimeDelta;
}
struct ViewHostMsg_CreateWindow_Params;
namespace content {
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 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 two functions provide the backend implementation of the
// corresponding functions in RenderProcessHost. See those declarations
// for documentation.
void ResumeDeferredNavigation(const GlobalRequestID& request_id);
// IO THREAD ONLY -----------------------------------------------------------
void CreateNewWindow(const ViewHostMsg_CreateWindow_Params& params,
bool no_javascript_access,
base::ProcessHandle render_process,
int32_t* route_id,
int32_t* main_frame_route_id,
int32_t* main_frame_widget_route_id,
SessionStorageNamespace* session_storage_namespace);
void CreateNewWidget(int opener_id,
blink::WebPopupType popup_type,
int* route_id);
void CreateNewFullscreenWidget(int opener_id, int* route_id);
private:
friend class base::RefCountedThreadSafe<RenderWidgetHelper>;
friend struct BrowserThread::DeleteOnThread<BrowserThread::IO>;
friend class base::DeleteHelper<RenderWidgetHelper>;
~RenderWidgetHelper();
// Called on the UI thread to finish creating a window.
void OnCreateWindowOnUI(const ViewHostMsg_CreateWindow_Params& params,
int32_t route_id,
int32_t main_frame_route_id,
int32_t main_frame_widget_route_id,
SessionStorageNamespace* session_storage_namespace);
// Called on the UI thread to finish creating a widget.
void OnCreateWidgetOnUI(int32_t opener_id,
int32_t route_id,
blink::WebPopupType popup_type);
// Called on the UI thread to create a fullscreen widget.
void OnCreateFullscreenWidgetOnUI(int32_t opener_id, int32_t route_id);
// Called on the IO thread to resume a paused navigation in the network
// stack without transferring it to a new renderer process.
void OnResumeDeferredNavigation(const GlobalRequestID& request_id);
// Called on the IO thread to resume a navigation paused immediately after
// receiving response headers.
void OnResumeResponseDeferredAtStart(const GlobalRequestID& request_id);
int render_process_id_;
// 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_
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