chrome PPAPI 开发（一）

    最近遇到一个需要在chrome49版本的浏览器上支持老版本 ActiveX 插件的问题。
    在网上翻来覆去找资料，最终的矛头都指向chrome的 PPAPI 开发，于是下载了一个ppapi的资源包。大家可从“我的资源”去下载。
    下面说一下如何开发一个可调试的ppapi 例子的过程。

    1. 环境准备
    安装Visual Studio。我的是VS2013。
    2. 解压ppapi 资源包到某个目录，例如 D://APIs/BHO-master/
    3. 在VS2013中新建一个最简单的 Win32 的DLL（C++ 工程），去掉StdAfx.h 和StdAfx.cpp 文件。
    4. 在工程主文件中输入代码。

#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <Windows.h>
#include <tchar.h>

#include "Win32Project1.h"

#include "ppapi/c/pp_completion_callback.h"
#include "ppapi/c/pp_errors.h"
#include "ppapi/c/pp_instance.h"
#include "ppapi/c/pp_module.h"
#include "ppapi/c/pp_rect.h"
#include "ppapi/c/pp_var.h"
#include "ppapi/c/ppb.h"
#include "ppapi/c/ppb_core.h"
#include "ppapi/c/ppb_graphics_2d.h"
#include "ppapi/c/ppb_image_data.h"
#include "ppapi/c/ppb_instance.h"
#include "ppapi/c/ppb_view.h"
#include "ppapi/c/ppp.h"
#include "ppapi/c/ppp_instance.h"
#include "ppapi/c/ppb_input_event.h"
#include "ppapi/c/ppp_input_event.h"

#include "ppapi/c/ppb_var.h"
#include "ppapi/c/ppb_var_dictionary.h"
#include "ppapi/c/ppb_var_array.h"
#include "ppapi/c/ppb_messaging.h"
#include "ppapi/c/ppp_messaging.h"
#include <stdlib.h>

PPB_GetInterface g_get_browser_interface = NULL;

const PPB_Core* g_core_interface;
const PPB_Graphics2D* g_graphics_2d_interface;
const PPB_ImageData* g_image_data_interface;
const PPB_Instance* g_instance_interface;
const PPB_View* g_view_interface;
const PPB_InputEvent *g_input_interface;
const PPB_MouseInputEvent *g_mouse_interface;

const PPB_Var* g_var_interface;
const PPB_VarDictionary *g_dictionary_interface;
const PPB_VarArray *g_array_interface;
const PPB_Messaging *g_message_interface;

/******foruok: create native window begin******/

static HWND g_child_window = NULL;
struct CreateChildWinParam {
    struct PP_Rect r;
    HWND hWndParent;
};
HANDLE g_hThread = NULL;
DWORD g_dwThreadId = 0;
BOOL g_bInProcess = 0;

static LRESULT CALLBACK VideoWindowProc(HWND hwnd,
    UINT uMsg,
    WPARAM wParam,
    LPARAM lParam
    )
{
    PAINTSTRUCT ps;
    HDC hdc;
    RECT r;
    TCHAR textIn[] = _T("Child Window(in-process)");
    TCHAR text[] = _T("Child Window(out-process)");
    switch (uMsg)
    {
    case WM_PAINT:
        GetClientRect(hwnd, &r);
        hdc = BeginPaint(hwnd, &ps);
        SetTextColor(hdc, RGB(0, 200, 0));
        FillRect(hdc, &r, (HBRUSH)GetStockObject(GRAY_BRUSH));
        if (g_bInProcess)
        {
            TextOut(hdc, 10, 50, textIn, ARRAYSIZE(textIn) - 1);
        }
        else
        {
            TextOut(hdc, 10, 50, text, ARRAYSIZE(text) - 1);
        }
        EndPaint(hwnd, &ps);
        return 0;
    }
    return DefWindowProc(hwnd, uMsg, wParam, lParam);
}

static void RegisterVideoWindowClass()
{
    WNDCLASSEX wcex = {
        /* cbSize = */ sizeof(WNDCLASSEX),
        /* style = */ CS_HREDRAW | CS_VREDRAW,
        /* lpfnWndProc = */ VideoWindowProc,
        /* cbClsExtra = */ 0,
        /* cbWndExtra = */ 0,
        /* hInstance = */ GetModuleHandle(NULL),
        /* hIcon = */ NULL,
        /* hCursor = */ LoadCursor(NULL, IDC_ARROW),
        /* hbrBackground = */ 0,
        /* lpszMenuName = */ NULL,
        /* lpszClassName = */ _T("_ChildWindowClass"),
        /* hIconSm = */ NULL,
    };
    RegisterClassEx(&wcex);
}

DWORD WINAPI ThreadProc(LPVOID lpParam)
{
    MSG msg;

    struct CreateChildWinParam *para = (struct CreateChildWinParam *)lpParam;

    TCHAR szLog[256] = { 0 };
    g_child_window = CreateWindowEx(0, _T("_ChildWindowClass"), _T("ChildWindow"),
        para->hWndParent == NULL ? (WS_OVERLAPPEDWINDOW | WS_VISIBLE) : (WS_CHILD | WS_VISIBLE | WS_DISABLED),
        para->r.point.x, para->r.point.y, para->r.size.width, para->r.size.height,
        para->hWndParent, NULL, GetModuleHandle(NULL), NULL);
    _stprintf_s(szLog, 256, _T("create child window(standalone msg loop) at (%d, %d) child = 0x%08x\r\n"),
        para->r.point.x, para->r.point.y,
        g_child_window);
    OutputDebugString(szLog);

    BOOL fGotMessage;
    while ((fGotMessage = GetMessage(&msg, (HWND)NULL, 0, 0)) != 0 && fGotMessage != -1)
    {
        TranslateMessage(&msg);
        if (msg.message == WM_USER && msg.hwnd == NULL)
        {
            OutputDebugString(_T("child window message loop quit\r\n"));
            g_dwThreadId = 0;
            g_hThread = NULL;
            g_child_window = NULL;
            return 0;
        }
        DispatchMessage(&msg);
    }
    return msg.wParam;
}

void CreateChildWindowOnMainThread(void *param, int32_t result)
{
    struct CreateChildWinParam *p = (struct CreateChildWinParam *)param;
    g_child_window = CreateWindowEx(0, _T("_ChildWindowClass"), _T("ChildWindow"),
        WS_CHILD | WS_VISIBLE,
        p->r.point.x, p->r.point.y, p->r.size.width, p->r.size.height,
        p->hWndParent, NULL, GetModuleHandle(NULL), NULL);
    TCHAR szLog[256] = { 0 };
    _stprintf_s(szLog, 256, _T("create child window(in-process) at (%d, %d) child = 0x%08x\r\n"),
        p->r.point.x, p->r.point.y,
        g_child_window);
    OutputDebugString(szLog);
    ShowWindow(g_child_window, SW_SHOW);
    UpdateWindow(g_child_window);
}

void CreateChildWindow(struct PP_Rect *r)
{
    HWND hwnd = FindWindowEx(NULL, NULL, _T("CefBrowserWindow"), NULL);
    HWND hwndWeb = FindWindowEx(hwnd, NULL, _T("Chrome_WidgetWin_0"), NULL);;
    /*if (hwndWeb)
    {
    hwndWeb = FindWindowEx(hwndWeb, NULL, _T("Chrome_RenderWidgetHostHWND"), NULL); //web contents
    }*/
    if (hwndWeb != NULL)OutputDebugString(_T("Got Chrome_RenderWidgetHostHWND\r\n"));
    DWORD pluginPid = GetCurrentProcessId();
    DWORD browserPid = 0;
    GetWindowThreadProcessId(hwnd, &browserPid);
    TCHAR szLog[256] = { 0 };
    _stprintf_s(szLog, 256, _T("Browser pid - %d, plugin pid - %d, brower hwnd - 0x%08x, webpage hwnd - 0x%08x\r\n"),
        browserPid, pluginPid, hwnd, hwndWeb);
    OutputDebugString(szLog);
    struct CreateChildWinParam *para = (CreateChildWinParam *)(struct PP_Rect *)malloc(sizeof(struct CreateChildWinParam));
    para->r = *r;
    para->hWndParent = hwndWeb;

    if (browserPid == pluginPid)
    {
        g_bInProcess = TRUE;
        g_core_interface->CallOnMainThread(0, PP_MakeCompletionCallback(CreateChildWindowOnMainThread, para), 0);
    }
    else
    {
        g_bInProcess = FALSE;
        g_hThread = CreateThread(NULL, 0, ThreadProc, para, 0, &g_dwThreadId);
        if (g_hThread != NULL)
        {
            OutputDebugString(_T("Launch child window thread.\r\n"));
        }
        else
        {
            OutputDebugString(_T("Launch child window thread FAILED!\r\n"));
        }
    }
}

/* PPP_Instance implementation -----------------------------------------------*/

struct InstanceInfo {
    PP_Instance pp_instance;
    struct PP_Size last_size;
    PP_Resource graphics;

    struct InstanceInfo* next;
};

/** Linked list of all live instances. */
struct InstanceInfo* all_instances = NULL;

/** Returns a refed resource corresponding to the created graphics 2d. */
PP_Resource MakeAndBindGraphics2D(PP_Instance instance,
    const struct PP_Size* size) {
    PP_Resource graphics;

    graphics = g_graphics_2d_interface->Create(instance, size, PP_FALSE);
    if (!graphics)
        return 0;

    if (!g_instance_interface->BindGraphics(instance, graphics)) {
        g_core_interface->ReleaseResource(graphics);
        return 0;
    }
    return graphics;
}

void FlushCompletionCallback(void* user_data, int32_t result) {
    /* Don't need to do anything here. */
}

unsigned int g_colors[4] = { 0xFF888888, 0xFFFF00FF, 0xFF00FFFF, 0xFFEA00FF };
unsigned int g_color_index = 0;

void Repaint(struct InstanceInfo* instance, const struct PP_Size* size) {
    PP_Resource image;
    struct PP_ImageDataDesc image_desc;
    uint32_t* image_data;
    int num_words, i;

    /* Ensure the graphics 2d is ready. */
    if (!instance->graphics) {
        instance->graphics = MakeAndBindGraphics2D(instance->pp_instance, size);
        if (!instance->graphics)
            return;
    }

    /* Create image data to paint into. */
    image = g_image_data_interface->Create(
        instance->pp_instance, PP_IMAGEDATAFORMAT_BGRA_PREMUL, size, PP_TRUE);
    if (!image)
        return;
    g_image_data_interface->Describe(image, &image_desc);

    /* Fill the image with blue. */
    image_data = (uint32_t*)g_image_data_interface->Map(image);
    if (!image_data) {
        g_core_interface->ReleaseResource(image);
        return;
    }
    num_words = image_desc.stride * size->height / 4;

    g_color_index++;
    if (g_color_index >= sizeof(g_colors) / sizeof(g_colors[0])) g_color_index = 0;

    for (i = 0; i < num_words; i++)
        image_data[i] = g_colors[g_color_index];

    /* Paint image to graphics 2d. */
    g_graphics_2d_interface->ReplaceContents(instance->graphics, image);
    g_graphics_2d_interface->Flush(instance->graphics,
        PP_MakeCompletionCallback(&FlushCompletionCallback, NULL));

    g_core_interface->ReleaseResource(image);
}

/** Returns the info for the given instance, or NULL if it's not found. */
struct InstanceInfo* FindInstance(PP_Instance instance) {
    struct InstanceInfo* cur = all_instances;
    while (cur) {
        if (cur->pp_instance == instance)
            return cur;
        cur = cur->next;
    }
    return NULL;
}

PP_Bool Instance_DidCreate(PP_Instance instance,
    uint32_t argc,
    const char* argn[],
    const char* argv[]) {
    struct InstanceInfo* info =
        (struct InstanceInfo*)malloc(sizeof(struct InstanceInfo));
    info->pp_instance = instance;
    info->last_size.width = 0;
    info->last_size.height = 0;
    info->graphics = 0;

    /* Insert into linked list of live instances. */
    info->next = all_instances;
    all_instances = info;

    g_input_interface->RequestInputEvents(instance, PP_INPUTEVENT_CLASS_MOUSE);
    g_input_interface->RequestFilteringInputEvents(instance, PP_INPUTEVENT_CLASS_MOUSE);

    OutputDebugString(_T("Instance_DidCreate\r\n"));

    return PP_TRUE;
}

void Instance_DidDestroy(PP_Instance instance) {
    /* Find the matching item in the linked list, delete it, and patch the
    * links.
    */
    struct InstanceInfo** prev_ptr = &all_instances;
    struct InstanceInfo* cur = all_instances;
    while (cur) {
        if (instance == cur->pp_instance) {
            *prev_ptr = cur->next;
            g_core_interface->ReleaseResource(cur->graphics);
            free(cur);
            return;
        }
        prev_ptr = &cur->next;
        cur = cur->next;
    }

    /**foruok: close native window**/
    if (g_child_window != NULL)SendMessage(g_child_window, WM_CLOSE, 0, 0);
    if (g_dwThreadId != 0)
    {
        OutputDebugString(_T("Plugin was destroyed, tell child window close and thread exit\r\n"));
        PostThreadMessage(g_dwThreadId, WM_USER, 0, 0);
    }
}

void Instance_DidChangeView(PP_Instance pp_instance,
    PP_Resource view) {
    struct PP_Rect position;
    struct InstanceInfo* info = FindInstance(pp_instance);
    if (!info)
        return;

    if (g_view_interface->GetRect(view, &position) == PP_FALSE)
        return;

    if (info->last_size.width != position.size.width ||
        info->last_size.height != position.size.height) {
        /* Got a resize, repaint the plugin. */
        Repaint(info, &position.size);
        info->last_size.width = position.size.width;
        info->last_size.height = position.size.height;

        /**foruok: call create window**/
        if (g_child_window == NULL)
        {
            CreateChildWindow(&position);
        }
    }

    OutputDebugString(_T("Instance_DidChangeView\r\n"));
}

void Instance_DidChangeFocus(PP_Instance pp_instance, PP_Bool has_focus) {
}

PP_Bool Instance_HandleDocumentLoad(PP_Instance pp_instance,
    PP_Resource pp_url_loader) {
    return PP_FALSE;
}

static PPP_Instance instance_interface = {
    &Instance_DidCreate,
    &Instance_DidDestroy,
    &Instance_DidChangeView,
    &Instance_DidChangeFocus,
    &Instance_HandleDocumentLoad
};

PP_Bool InputEvent_HandleInputEvent(PP_Instance instance, PP_Resource input_event)
{
    struct PP_Point pt;
    TCHAR szLog[512] = { 0 };
    switch (g_input_interface->GetType(input_event))
    {
    case PP_INPUTEVENT_TYPE_MOUSEDOWN:
        pt = g_mouse_interface->GetPosition(input_event);
        _stprintf_s(szLog, 512, _T("InputEvent_HandleInputEvent, mouse down at [%d, %d]\r\n"), pt.x, pt.y);
        OutputDebugString(szLog);
        break;
        /*
        case PP_INPUTEVENT_TYPE_MOUSEUP:
        OutputDebugString(_T("InputEvent_HandleInputEvent, mouse up\r\n"));
        break;

        case PP_INPUTEVENT_TYPE_MOUSEMOVE:
        OutputDebugString(_T("InputEvent_HandleInputEvent, mouse move\r\n"));
        break;
        case PP_INPUTEVENT_TYPE_MOUSEENTER:
        OutputDebugString(_T("InputEvent_HandleInputEvent, mouse enter\r\n"));
        break;
        case PP_INPUTEVENT_TYPE_MOUSELEAVE:
        OutputDebugString(_T("InputEvent_HandleInputEvent, mouse leave\r\n"));
        break;
        */
    default:
        return PP_FALSE;
    }
    struct InstanceInfo* info = FindInstance(instance);
    if (info && info->last_size.width > 0)
    {
        Repaint(info, &info->last_size);
    }
    return PP_TRUE;
}

static PPP_InputEvent input_interface = {
    &InputEvent_HandleInputEvent
};

/* Global entrypoints --------------------------------------------------------*/

PP_EXPORT int32_t PPP_InitializeModule(PP_Module module,
    PPB_GetInterface get_browser_interface) {

    /**foruok: register window class**/
    RegisterVideoWindowClass();

    g_get_browser_interface = get_browser_interface;

    g_core_interface = (const PPB_Core*)
        get_browser_interface(PPB_CORE_INTERFACE);
    g_instance_interface = (const PPB_Instance*)
        get_browser_interface(PPB_INSTANCE_INTERFACE);
    g_image_data_interface = (const PPB_ImageData*)
        get_browser_interface(PPB_IMAGEDATA_INTERFACE);
    g_graphics_2d_interface = (const PPB_Graphics2D*)
        get_browser_interface(PPB_GRAPHICS_2D_INTERFACE);
    g_view_interface = (const PPB_View*)
        get_browser_interface(PPB_VIEW_INTERFACE);
    g_input_interface = (const PPB_InputEvent*)get_browser_interface(PPB_INPUT_EVENT_INTERFACE);
    g_mouse_interface = (const PPB_MouseInputEvent*)get_browser_interface(PPB_MOUSE_INPUT_EVENT_INTERFACE);

    if (!g_core_interface || !g_instance_interface || !g_image_data_interface ||
        !g_graphics_2d_interface || !g_view_interface ||
        !g_input_interface || !g_mouse_interface)
        return -1;

    g_var_interface = (const PPB_Var*)get_browser_interface(PPB_VAR_INTERFACE);
    g_dictionary_interface = (const PPB_VarDictionary*)get_browser_interface(PPB_VAR_DICTIONARY_INTERFACE);
    g_array_interface = (const PPB_VarArray*)get_browser_interface(PPB_VAR_ARRAY_INTERFACE);
    g_message_interface = (const PPB_Messaging*)get_browser_interface(PPB_MESSAGING_INTERFACE);

    OutputDebugString(_T("PPP_InitializeModule\r\n"));
    return PP_OK;
}

PP_EXPORT void PPP_ShutdownModule() {
}

void Plugin_HandleMessage(PP_Instance instance, struct PP_Var message)
{
    char szLog[256] = { 0 };
    //sprintf_s(szLog, 256, "Plugin_HandleMessage, type = %d\r\n", message.type);
    OutputDebugStringA(szLog);

    if (message.type == PP_VARTYPE_DICTIONARY)
    {
        char command[] = "command";
        struct PP_Var commandKey = g_var_interface->VarFromUtf8(command, sizeof(command)-1);
        struct PP_Var commandVar = g_dictionary_interface->Get(message, commandKey);
        int len = 0;
        const char *strCommand = g_var_interface->VarToUtf8(commandVar, (uint32_t*)&len);
        g_var_interface->Release(commandKey);

        //sprintf_s(szLog, 256, "Plugin_HandleMessage, dict, command = %s, len = %d\r\n", strCommand, len);
        OutputDebugStringA(szLog);

        if (len == 0)
        {
            OutputDebugString(_T("Tang_plugin, recv invalid command\r\n"));
            g_var_interface->Release(commandVar);
            return;
        }
        if (strncmp(strCommand, "joinConf", len) == 0)
        {
            char confIdKey[] = "confId";
            char userNameKey[] = "userName";
            char *szConfId = 0;
            char*szUserName = 0;
            struct PP_Var idKey = g_var_interface->VarFromUtf8(confIdKey, sizeof(confIdKey)-1);
            struct PP_Var userKey = g_var_interface->VarFromUtf8(userNameKey, sizeof(userNameKey)-1);
            struct PP_Var var = g_dictionary_interface->Get(message, idKey);
            const char *value = g_var_interface->VarToUtf8(var, (uint32_t*)&len);
            if (len > 0)
            {
                szConfId = (char*)malloc(len + 1);
                strncpy_s(szConfId, len + 1, value, len);
                szConfId[len] = 0;
            }
            g_var_interface->Release(var);

            var = g_dictionary_interface->Get(message, userKey);
            value = g_var_interface->VarToUtf8(var, (uint32_t*)&len);
            if (len > 0)
            {
                szUserName = (char*)malloc(len + 1);
                strncpy_s(szUserName, len + 1, value, len);
                szUserName[len] = 0;
            }
            g_var_interface->Release(var);

            //sprintf_s(szLog, 256, "Plugin_HandleMessage, dict, command = joinConf, user = %s, confId = %s\r\n", szUserName, szConfId);
            OutputDebugStringA(szLog);

            if (szConfId && szUserName)
            {
                //sprintf_s(szLog, 256, "plugin got confId - %s, user - %s\r\n", szConfId, szUserName);
                OutputDebugStringA(szLog);
                //joinConf(szConfId, szUserName);
            }
            else
            {
                OutputDebugString(_T("Invalid conference id or userName\r\n"));
            }
            if (szConfId) free(szConfId);
            if (szUserName) free(szUserName);
            g_var_interface->Release(idKey);
            g_var_interface->Release(userKey);

            /* fake attendees*/
            char szMsgTypeValue[] = "userlist";
            char szTypeKey[] = "type";
            struct PP_Var typeKey = g_var_interface->VarFromUtf8(szTypeKey, sizeof(szTypeKey)-1);
            struct PP_Var typeValue = g_var_interface->VarFromUtf8(szMsgTypeValue, sizeof(szMsgTypeValue)-1);
            struct PP_Var attendee = g_dictionary_interface->Create();
            g_dictionary_interface->Set(attendee, typeKey, typeValue);

            struct PP_Var userArray = g_array_interface->Create();
            char szUser1[] = "ZhangSan";
            char szUser2[] = "LiSi";
            struct PP_Var user1 = g_var_interface->VarFromUtf8(szUser1, sizeof(szUser1)-1);
            struct PP_Var user2 = g_var_interface->VarFromUtf8(szUser2, sizeof(szUser2)-1);
            g_array_interface->Set(userArray, 0, user1);
            g_array_interface->Set(userArray, 1, user2);

            char szValueKey[] = "value";
            struct PP_Var valueKey = g_var_interface->VarFromUtf8(szValueKey, sizeof(szValueKey)-1);
            g_dictionary_interface->Set(attendee, valueKey, userArray);

            g_message_interface->PostMessage(instance, attendee);
            OutputDebugString(_T("Post attendee to browser"));

            g_var_interface->Release(typeKey);
            g_var_interface->Release(typeValue);
            g_var_interface->Release(user1);
            g_var_interface->Release(user2);
            g_var_interface->Release(valueKey);
            g_var_interface->Release(userArray);
            g_var_interface->Release(attendee);
        }
        else if (strncmp(strCommand, "viewVideo", len) == 0)
        {
            char userIdKey[] = "userId";
            char *szUserId = 0;
            struct PP_Var idKey = g_var_interface->VarFromUtf8(userIdKey, sizeof(userIdKey)-1);
            struct PP_Var var = g_dictionary_interface->Get(message, idKey);
            const char *value = g_var_interface->VarToUtf8(var, (uint32_t*)&len);
            if (len > 0)
            {
                szUserId = (char*)malloc(len + 1);
                strncpy_s(szUserId, len + 1, value, len);
                szUserId[len] = 0;
            }
            if (szUserId)
            {
                //sprintf_s(szLog, 256, "plugin got userId - %s\r\n", szUserId);
                OutputDebugStringA(szLog);
                //viewVideo(szUserId, g_child_window);
            }
            else
            {
                OutputDebugString(_T("Invalid viewVideo command without userId\r\n"));
            }
            if (szUserId) free(szUserId);
            g_var_interface->Release(var);
            g_var_interface->Release(idKey);
        }
        g_var_interface->Release(commandVar);
    }
    else if (message.type == PP_VARTYPE_STRING)
    {
        char hello_world[] = "Hello world!";
        struct PP_Var var = g_var_interface->VarFromUtf8(hello_world, sizeof(hello_world)-1);
        g_message_interface->PostMessage(instance, var); // var will be copyed
        g_var_interface->Release(var);
    }
}

static PPP_Messaging message_interface = {
    &Plugin_HandleMessage
};

PP_EXPORT const void* PPP_GetInterface(const char* interface_name) {
    if (strcmp(interface_name, PPP_INSTANCE_INTERFACE) == 0)
    {
        OutputDebugString(_T("PPP_GetInterface, instance_interface\r\n"));
        return &instance_interface;
    }
    else if (strcmp(interface_name, PPP_INPUT_EVENT_INTERFACE) == 0)
    {
        OutputDebugString(_T("PPP_GetInterface, input_interface\r\n"));
        return &input_interface;
    }
    else if (strcmp(interface_name, PPP_MESSAGING_INTERFACE) == 0)
    {
        OutputDebugString(_T("PPP_GetInterface, message_interface\r\n"));
        return &message_interface;
    }

    return NULL;
}

 

    5. 右键选择工程属性，在工程的包含目录中加入  D://APIs/BHO-master/
    6. 编译工程得到一个 dll，例如 ppapiexample.dll。
    7. 编写一个cef.html 文件，

<!DOCTYPE html>
<html>
  <!--
  Copyright (c) 2016 foruok@微信订阅号“程序视界”(programmer_sight). 
  All rights reserved.
  Use of this source code is governed by a BSD-style license that can be
  found in the LICENSE file.
  -->
<head>
    <style type="text/css">
    #contacts
    {
        margin: 10px;
        width: 300px;
        height: 200px;
        background-color: gray;
    }
    </style>
    <script type="text/javascript">
      function handleMessage(message) {
        alert(message.data.type);
        if(message.data.type.localeCompare("userlist") == 0){
          var i = 0;
          ul = document.getElementById("attendee");
          for(; i < message.data.value.length; i++){
            var li = document.createElement("li");
            li.appendChild(document.createTextNode(message.data.value[i]));
            ul.appendChild(li);
          }
        }
      }

      function joinConference(){
        plugin = document.getElementById('tangplugin');
        plugin.postMessage({
            command:"joinConf", 
            confId: document.getElementById("confId").value, 
            userName: document.getElementById("userName").value
          });
      }
      function viewSharedVideo(){
        plugin = document.getElementById('tangplugin');
        plugin.postMessage({
            command:"viewVideo", 
            userId: document.getElementById("userId").value
          });
      }

      function initialize() {
        plugin = document.getElementById('tangplugin');
        plugin.addEventListener('message', handleMessage, false);
      }

      document.addEventListener('DOMContentLoaded', initialize, false);
    </script>
  <title>Tang in Plugin</title>
</head>

<body>
<form>
ConferenceID: <input type="text" id="confId" />&nbsp;&nbsp;User: 
<input type="text" id="userName" />&nbsp;&nbsp;<input  type="button" value="Join" onclick="joinConference()"/>
</form>
<hr>
<div id="contacts">
<p>contacts:</p>
<ul id="attendee">
  <!--
  here will show attendee list, added by JS callback
  -->
</ul>
UserId:<input type="text" id="userId" />&nbsp;&nbsp;<button type="button" onclick="viewSharedVideo()">View Video</button>
</div>

<p>share video:</p>
<embed id="tangplugin" type="application/x-ppapi-tang-video" width="300px" height="200px" top="40px" left="20px">

</body>
</html>

    8. 制作一个 .bat 文件，文件内容类似如下：
chrome --register-pepper-
plugins="C:\\Users\\Administrator\\AppData\\Local\\Google\\Chrome\\Application\\49.0.2623.110\\tplugin\\ppapiexample.dll;application/x-ppapi-tang-video"  D:\\APIs\\BHO-master\\cef.html
    9.  运行该 .bat 文件，查看效果。