Improve camera capability of the file chooser

This builds on LuckyLuky's [commit](LuckyLuky@876a12a) in [PR apache#857](apache#857) to improve the camera path for file inputs (`<input type="file"/>`) on Android.

The changes are:

- Light refactoring to extract work such as configuring the intent into functions
- Only offer the "Image Capture" intent if the device has a camera app and the file input has an accept type of an image (e.g. "image/png" or "image/*")
- Use a cache directory to store files, rather than the external storage. This mimics how cordova-plugin-camera stores files.
- Mark the photos for later deletion with `deleteOnExit`. I'm not sure how robust this is, so if we truly wanted to clean up files, we would need to do it explicitly, each time `onShowFileChooser` was fired.

Both the change in the original commit and in this one rely on the FileProvider API to allow the passing of content URIs (rather than File URIs) between this plugin and the camera app. As such, the FileProvider must be configured. The Camera Plugin does this in plugin.xml, but no such change has been made here yet. Therefore, configuration similar to the following must be added to the main app.

```xml
<!-- config.xml -->
<widget>
  ...
  <platform name="android">
    <!-- Configure our FileProvider-->
    <config-file target="AndroidManifest.xml" parent="application">
      <provider
        android:name="androidx.core.content.FileProvider"
        android:authorities="YOUR_APP_ID.fileprovider"
        android:exported="false"
        android:grantUriPermissions="true">
        <meta-data
          android:name="android.support.FILE_PROVIDER_PATHS"
          android:resource="@xml/camera_provider_paths"
        />
      </provider>
    </config-file>
    <resource-file src="camera_provider_paths.xml" target="app/src/main/res/xml/camera_provider_paths.xml" />
  </platform>
  ...
</widget>
```

```xml
<!-- camera_provider_paths.xml -->
<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
  <cache-path name="cache_files" path="." />
</paths>
```

Fore more information on the above configuration, see the ["Take photos" Guide on Android Developers](https://developer.android.com/training/camera/photobasics)

The following improvements could be made to this feature of the plugin:

- Use the `captureEnabled()` boolean on the file chooser params to only offer the camera when capture is enabled on the HTML element
- Image downscaling - it would be very nice to allow control over the quality and size of the captured image. But, at this point, could we just delegate to the existing Camera plugin? (cordova-plugin-camera)

Author: moklett

src/android/InAppBrowser.java

@@ -85,7 +85,6 @@ Licensed to the Apache Software Foundation (ASF) under one
 import java.util.StringTokenizer;
 
 import android.Manifest;
-import android.os.Environment;
 import android.provider.MediaStore;
 import android.util.Log;
 import androidx.core.content.FileProvider;
@@ -161,7 +160,7 @@ public class InAppBrowser extends CordovaPlugin {
     private boolean fullscreen = true;
     private String[] allowedSchemes;
     private InAppBrowserClient currentClient;
-    private String photoFilePath;
+    private File photoFile;
     private Uri photoFileUri;
 
     /**
@@ -951,29 +950,13 @@ public boolean onShowFileChooser (WebView webView, ValueCallback<Uri[]> filePath
                         }
                         mUploadCallback = filePathCallback;
 
-                        Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
-
-                        if (takePictureIntent.resolveActivity(cordova.getActivity().getPackageManager()) != null) {
-
-                            File photoFile = null;
-                            try {
-                                photoFile = createImageFile();
-                                takePictureIntent.putExtra("PhotoPath", photoFilePath);
-                            } catch (IOException ex) {
-                                Log.e(LOG_TAG, "Image file creation failed", ex);
-                            }
-                            if (photoFile != null) {
-                                photoFilePath = "file:/" + photoFile.getAbsolutePath();
-                                photoFileUri = FileProvider.getUriForFile(
-                                        cordova.getActivity().getApplicationContext(),
-                                        cordova.getActivity().getPackageName() + ".fileprovider",
-                                        photoFile
-                                );
-                                takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, photoFileUri);
-                            } else {
-                                takePictureIntent = null;
-                            }
+                        // Set up the intent to take a picture, if the file input has the capture attribute and any `image/` in the accept attribute.
+                        // Ex: <input type="file" accept="image/*" capture />
+                        Intent takePictureIntent = null;
+                        if (shouldOfferCameraForFileInput(fileChooserParams)) {
+                            takePictureIntent = buildTakePictureIntent();
                         }
+
                         // Create File Chooser Intent
                         Intent contentSelectionIntent = new Intent(Intent.ACTION_GET_CONTENT);
                         contentSelectionIntent.addCategory(Intent.CATEGORY_OPENABLE);
@@ -1132,9 +1115,54 @@ public void postMessage(String data) {
     private File createImageFile() throws IOException{
         @SuppressLint("SimpleDateFormat") String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
         String imageFileName = "img_"+timeStamp+"_";
-        File storageDir = this.cordova.getActivity().getExternalFilesDir(Environment.DIRECTORY_PICTURES);
-        File file = new File(storageDir, imageFileName + ".jpg");
-        return file;
+        File cacheDir = this.cordova.getActivity().getCacheDir();
+        // Create the cache directory if it doesn't exist
+        cacheDir.mkdirs();
+        return new File(cacheDir.getAbsolutePath(), imageFileName + ".jpg");
+    }
+
+    // Returns true if there is a system camera and the accept types on the file input want an image (e.g. image/png or image/*).
+    // Note: another good indicator would be to check fileChooserParams.isCaptureEnabled(), but that is not done here.
+    private boolean shouldOfferCameraForFileInput(WebChromeClient.FileChooserParams fileChooserParams) {
+        boolean hasCamera = cordova.getActivity().getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA_ANY);
+        boolean wantsImage = false;
+        for (String acceptType : fileChooserParams.getAcceptTypes()) {
+          if (acceptType.startsWith("image/")) {
+            wantsImage = true;
+            break;
+          }
+        }
+
+        return hasCamera && wantsImage;
+    }
+
+    private Intent buildTakePictureIntent() {
+        Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
+
+        photoFile = null;
+        try {
+            photoFile = createImageFile();
+        } catch (IOException ex) {
+            Log.e(LOG_TAG, "Image file creation failed", ex);
+        }
+        if (photoFile != null) {
+            try {
+                // Compute the Content URI for our file. See: https://developer.android.com/training/camera/photobasics#TaskPath
+                photoFileUri = FileProvider.getUriForFile(
+                    cordova.getActivity().getApplicationContext(),
+                    cordova.getActivity().getPackageName() + ".fileprovider",
+                    photoFile
+                );
+                takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, photoFileUri);
+            } catch(IllegalArgumentException ex) {
+                Log.e(LOG_TAG, "File provider initialization failed - configure your FileProvider in the app manifest", ex);
+                takePictureIntent = null;
+            }
+        } else {
+            takePictureIntent = null;
+        }
+
+        return takePictureIntent;
     }
 
     /**
@@ -1188,6 +1216,9 @@ public void onActivityResult(int requestCode, int resultCode, Intent intent) {
         }
         mUploadCallback.onReceiveValue(WebChromeClient.FileChooserParams.parseResult(resultCode, customIntent));
         mUploadCallback = null;
+        if (photoFile != null) {
+          photoFile.deleteOnExit();
+        }
     }
 
     /**