无法在webRTC上下文中从Android webView（chrome框架）访问相机

应用基于webRTC vs websocket。Android Studio 2.3.2最新版本。

我已经使用：

https协议，自动播放，android版本7.0（最低> android 5.0）。该应用程序可在所有受支持的浏览器上运行，仅android webview会产生错误。

这是登录logcat的第一行错误（android studio最新版本）：

E /铬：[ERROR：audio_manager_android.cc（264）]无法选择音频设备！E / cr_VideoCapture：分配：manager.openCamera：SecurityException：validateConnectLocked：1112：调用者“ com.testwebrtc.nikola.myapplication”在没有android.hardware.camera2.CameraManager.throwAsPublicException（CameraManager.java： 628）在android.hardware.camera2.CameraManager.openCameraDeviceUserAsync（CameraManager.java:347）在android.hardware.camera2.CameraManager.openCamera（CameraManager.java:450）在org.chromium.media.VideoCaptureCamera2.startCapture（VideoCaptureCamera2.java ：661）

错误的其他变体：

[ERROR：web_contents_delegate.cc（199）] WebContentsDelegate :: CheckMediaAccessPermission：不支持。

这是来自chrome / webview的错误日志（来自errorCallBack-getUserMedia）：

      An error occcurred [CODE NotAllowedError]

      other error variant: 

      trackstarterror

Android代码如下所示：

package com.project.TEST.xxx;
import android.annotation.TargetApi;
import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentManager;
import android.content.Context;
import android.os.Build;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.webkit.CookieManager;
import android.webkit.PermissionRequest;
import android.webkit.WebChromeClient;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    private static final String TAG = MainActivity.class.getSimpleName();


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        FragmentManager fragmentManager = getFragmentManager();
        fragmentManager.beginTransaction()
                .replace(R.id.container, PlaceholderFragment.newInstance(1) )
                .commit();

    }

    /**
     * A placeholder fragment containing a simple view.
     */
    public static class PlaceholderFragment extends Fragment {
        /**
         * The fragment argument representing the section number for this
         * fragment.
         */
        private static final String ARG_SECTION_NUMBER = "section_number";

        /**
         * Returns a new instance of this fragment for the given section
         * number.
         */
        public static PlaceholderFragment newInstance(int sectionNumber) {
            PlaceholderFragment fragment = new PlaceholderFragment();
            Bundle args = new Bundle();
            args.putInt(ARG_SECTION_NUMBER, sectionNumber);
            fragment.setArguments(args);
            return fragment;
        }

        private WebView mWebRTCWebView;

        public PlaceholderFragment() {
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                 Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_main, container, false);
            mWebRTCWebView = (WebView) rootView.findViewById(R.id.fragment_main_webview);

            setUpWebViewDefaults(mWebRTCWebView);

            mWebRTCWebView.loadUrl("https://example.com/");

            mWebRTCWebView.setWebChromeClient(new WebChromeClient() {

                @Override
                public void onPermissionRequest(final PermissionRequest request) {
                    Log.d(TAG, "onPermissionRequest");
                    getActivity().runOnUiThread(new Runnable() {
                        @TargetApi(Build.VERSION_CODES.LOLLIPOP)
                        @Override
                        public void run() {

                            request.grant(request.getResources());

                        }
                    });
                }

            });

            return rootView;
        }

        @Override
        public void onStop() {
            super.onStop();

            /**
             * When the application falls into the background we want to stop the media stream
             * such that the camera is free to use by other apps.
             */
            mWebRTCWebView.evaluateJavascript("if(window.localStream){window.localStream.stop();}", null);
        }

        /*
        @Override
        public void onAttach(Activity activity) {
            super.onAttach(activity);
            ((MainActivity) activity).onSectionAttached(
                    getArguments().getInt(ARG_SECTION_NUMBER));
        }
*/

        @Override
        public void onAttach(Context context) {
            super.onAttach(context);

            Activity a;

            if (context instanceof Activity){
                a=(Activity) context;

            }

        }

        /**
         * Convenience method to set some generic defaults for a
         * given WebView
         *
         * @param webView
         */
        @TargetApi(Build.VERSION_CODES.LOLLIPOP)
        private void setUpWebViewDefaults(WebView webView) {
            WebSettings settings = webView.getSettings();

            // Enable Javascript
            settings.setJavaScriptEnabled(true);

            // Use WideViewport and Zoom out if there is no viewport defined
            settings.setUseWideViewPort(true);
            settings.setLoadWithOverviewMode(true);

            // Enable pinch to zoom without the zoom buttons
            settings.setBuiltInZoomControls(true);

            // Allow use of Local Storage
            settings.setDomStorageEnabled(true);

            if(Build.VERSION.SDK_INT > Build.VERSION_CODES.HONEYCOMB) {
                // Hide the zoom controls for HONEYCOMB+
                settings.setDisplayZoomControls(false);
            }

            // Enable remote debugging via chrome://inspect
            if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
                WebView.setWebContentsDebuggingEnabled(true);
            }

            webView.setWebViewClient(new WebViewClient());

            // AppRTC requires third party cookies to work
            CookieManager cookieManager = CookieManager.getInstance();
            cookieManager.setAcceptThirdPartyCookies(mWebRTCWebView, true);
        }
    }


}

Build.gradle-project：

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:2.3.2'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        jcenter()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

gradle-模块：

apply plugin: 'com.android.application'

android {
    compileSdkVersion 25
    buildToolsVersion "25.0.3"
    defaultConfig {
        applicationId "com.project.test.xxx"
        minSdkVersion 21
        targetSdkVersion 25
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
        externalNativeBuild {
            cmake {
                cppFlags "-fexceptions"
            }
        }
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    externalNativeBuild {
        cmake {
            path "CMakeLists.txt"
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    compile 'com.android.support:appcompat-v7:25.3.1'
    compile 'com.android.support.constraint:constraint-layout:1.0.2'
    testCompile 'junit:junit:4.12'
}

Android Manifest.xml：

....
  <uses-permission android:name="android.permission.CAMERA" />
    <uses-permission android:name="android.permission.CAPTURE_SECURE_VIDEO_OUTPUT" />
    <uses-permission android:name="android.permission.CAPTURE_VIDEO_OUTPUT" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.RECORD_AUDIO" />

    <uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />
    <uses-permission android:name="android.permission.CAPTURE_AUDIO_OUTPUT" />
    <uses-feature android:name="android.hardware.camera.autofocus" android:required="true" />
    <uses-feature android:name="android.hardware.camera.front" android:required="true" />
    <uses-feature android:name="android.hardware.camera" android:required="true" />
    <uses-feature android:name="android.hardware.camera.level.full" android:required="true" />
    <uses-feature android:name="android.hardware.camera.capability.raw" android:required="true" />
    <uses-feature android:name="android.hardware.camera.any" android:required="true" />
    <uses-feature android:name="android.hardware.microphone" android:required="true" />
    <uses-feature android:name="android.hardware.camera2" android:required="true" />

...