chromedriver.switchTo().frame(webview) crashes when testing a chrome app - selenium

Question

I have a chrome app inside which there is a webview. To run functional tests, I need to click elements inside this webview but driver.switchTo().frame(webview) crashes with exception org.openqa.selenium.NoSuchFrameException.
Sample code :
System.setProperty("webdriver.chrome.driver", "/home/janindua/Software/chromeDriver/chromedriver");
ChromeOptions options = new ChromeOptions();
options.addExtensions(new File("/home/janindua/workspace/discovery-ui/scraper2/build/target/scraper.crx"));
DesiredCapabilities capabilities = new DesiredCapabilities();
capabilities.setCapability(ChromeOptions.CAPABILITY, options);
ChromeDriver driver = new ChromeDriver(capabilities);
driver.get("chrome-extension://monoimhdfegpapbgppdmjfdgjdbkpboi/window.html");
driver.navigate().refresh();
driver.findElement(By.id("weburl-txtbox")).sendKeys("http://google.com/");
driver.findElementById("weburl-btn").click();
Thread.sleep(10000);
WebElement we = driver.findElementById("webv");
driver.switchTo().frame(we);
window html :
Stack trace :
Exception in thread "main" org.openqa.selenium.NoSuchFrameException: no such frame: element is not a frame
(Session info: chrome=42.0.2311.135)
(Driver info: chromedriver=2.16.333243
(0bfa1d3575fc1044244f21ddb82bf870944ef961),platform=Linux 3.13.0-24-generic x86_64) (WARNING: The server did not provide any stacktrace information)
Command duration or timeout: 9 milliseconds
Build info: version: '2.46.0', revision: '87c69e2', time: '2015-06-04 16:17:10'
System info: host: 'janindua', ip: '127.0.1.1', os.name: 'Linux', os.arch: 'amd64', os.version: '3.13.0-24-generic', java.version: '1.7.0_80'
Session ID: 878af1ba4a28469360756d6f786f6510
Driver info: org.openqa.selenium.chrome.ChromeDriver
Capabilities [{platform=LINUX, acceptSslCerts=true, javascriptEnabled=true, browserName=chrome, chrome={userDataDir=/tmp/.com.google.Chrome.ZJ2D7R}, rotatable=false, locationContextEnabled=true, mobileEmulationEnabled=false, version=42.0.2311.135, takesHeapSnapshot=true, cssSelectorsEnabled=true, databaseEnabled=false, handlesAlerts=true, browserConnectionEnabled=false, webStorageEnabled=true, nativeEvents=true, hasTouchScreen=false, applicationCacheEnabled=false, takesScreenshot=true}]
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
at org.openqa.selenium.remote.ErrorHandler.createThrowable(ErrorHandler.java:204)
at org.openqa.selenium.remote.ErrorHandler.throwIfResponseFailed(ErrorHandler.java:156)
at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:605)
at org.openqa.selenium.remote.RemoteWebDriver$RemoteTargetLocator.frame(RemoteWebDriver.java:895)
at Google.main(Google.java:26)

Answer 1

janindu's answer is no longer correct (Partialy).
Since Oct 2015 there is a proper method to get webviews window handle
How to:
We will need to inform the driver that we want it to handler webviews window handlers
(The chromeOptions & windowTypes are the important parts)
It suppose to look something like this
capabilities: {
'browserName': 'chrome',
'chromeOptions': {
'windowTypes': ['webview']
}
},
After that, you can get the window handler in the usual way,
browser.getAllWindowHandles()

Answer 2

Right now this is a known bug, reported as Issue 960
If your chrome app uses a webview to load a web page and you want to run some automated scripts, chromedriver does not provide a method to access the elements in the web page loaded inside the webview.
Both chromedriver.switchTo().frame(webview) and chromedriver.switchTo().window(webview) methods will throw exceptions as webviews are not acceptable inputs to either method.