android4.0 webkit 请求网络数据的调用流程

1.
PassRefPtr<ResourceLoaderAndroid> ResourceLoaderAndroid::start(
        ResourceHandle* handle, const ResourceRequest& request, FrameLoaderClient* client, bool isMainResource, bool isSync)
{
    // Called on main thread
    FrameLoaderClientAndroid* clientAndroid = static_cast<FrameLoaderClientAndroid*>(client);
#if USE(CHROME_NETWORK_STACK)
    WebViewCore* webViewCore = WebViewCore::getWebViewCore(clientAndroid->getFrame()->view());
    bool isMainFrame = !(clientAndroid->getFrame()->tree() && clientAndroid->getFrame()->tree()->parent());
    return WebUrlLoader::start(client, handle, request, isMainResource, isMainFrame, isSync, webViewCore->webRequestContext());
#else
    return clientAndroid->webFrame()->startLoadingResource(handle, request, isMainResource, isSync);
#endif
}

PassRefPtr<WebCore::ResourceLoaderAndroid>
WebFrame::startLoadingResource(WebCore::ResourceHandle* loader,
                                  const WebCore::ResourceRequest& request,
                                  bool mainResource,
                                  bool synchronous)
{
#ifdef ANDROID_INSTRUMENT
    TimeCounterAuto counter(TimeCounter::JavaCallbackTimeCounter);
#endif
    LOGV("::WebCore:: startLoadingResource(%p, %s)",
            loader, request.url().string().latin1().data());

    JNIEnv* env = getJNIEnv();
    AutoJObject javaFrame = mJavaFrame->frame(env);
    if (!javaFrame.get())
        return 0;

WTF::String method = request.httpMethod();
WebCore::HTTPHeaderMap headers = request.httpHeaderFields();

    WTF::String urlStr = request.url().string();
    int colon = urlStr.find(':');
    bool allLower = true;
    for (int index = 0; index < colon; index++) {
        UChar ch = urlStr[index];
        if (!WTF::isASCIIAlpha(ch))
            break;
        allLower &= WTF::isASCIILower(ch);
        if (index == colon - 1 && !allLower) {
            urlStr = urlStr.substring(0, colon).lower()
                    + urlStr.substring(colon);
        }
    }
    LOGV("%s lower=%s", __FUNCTION__, urlStr.latin1().data());
    jstring jUrlStr = wtfStringToJstring(env, urlStr);
    jstring jMethodStr = NULL;
    if (!method.isEmpty())
        jMethodStr = wtfStringToJstring(env, method);
    WebCore::FormData* formdata = request.httpBody();
    jbyteArray jPostDataStr = getPostData(request);
    jobject jHeaderMap = createJavaMapFromHTTPHeaders(env, headers);

    // Convert the WebCore Cache Policy to a WebView Cache Policy.
    int cacheMode = 0; // WebSettings.LOAD_NORMAL
    switch (request.cachePolicy()) {
        case WebCore::ReloadIgnoringCacheData:
            cacheMode = 2; // WebSettings.LOAD_NO_CACHE
            break;
        case WebCore::ReturnCacheDataDontLoad:
            cacheMode = 3; // WebSettings.LOAD_CACHE_ONLY
            break;
        case WebCore::ReturnCacheDataElseLoad:
            cacheMode = 1;   // WebSettings.LOAD_CACHE_ELSE_NETWORK
            break;
        case WebCore::UseProtocolCachePolicy:
        default:
            break;
    }

LOGV("::WebCore:: startLoadingResource %s with cacheMode %d", urlStr.ascii().data(), cacheMode);

    ResourceHandleInternal* loaderInternal = loader->getInternal();
    jstring jUsernameString = loaderInternal->m_user.isEmpty() ?
            NULL : wtfStringToJstring(env, loaderInternal->m_user);
    jstring jPasswordString = loaderInternal->m_pass.isEmpty() ?
            NULL : wtfStringToJstring(env, loaderInternal->m_pass);

    bool isUserGesture = UserGestureIndicator::processingUserGesture();
    jobject jLoadListener =
        env->CallObjectMethod(javaFrame.get(), mJavaFrame->mStartLoadingResource,
                (int)loader, jUrlStr, jMethodStr, jHeaderMap,
                jPostDataStr, formdata ? formdata->identifier(): 0,
                cacheMode, mainResource, isUserGesture,
                synchronous, jUsernameString, jPasswordString);

    env->DeleteLocalRef(jUrlStr);
    env->DeleteLocalRef(jMethodStr);
    env->DeleteLocalRef(jPostDataStr);
    env->DeleteLocalRef(jHeaderMap);
    env->DeleteLocalRef(jUsernameString);
    env->DeleteLocalRef(jPasswordString);
    if (checkException(env))
        return 0;

    PassRefPtr<WebCore::ResourceLoaderAndroid> h;
    if (jLoadListener)
        h = WebCoreResourceLoader::create(env, jLoadListener);
    env->DeleteLocalRef(jLoadListener);
    return h;
}

3.
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补充：移动开发 , Android ,