Use FileProvider for installing WebAPKs on Android N

Android N now bans installing APKs from world readable files and requires
FileProvider. See http://stackoverflow.com/questions/36755301/how-to-run-install-app-in-internal-files-dir

BUG=663800

Review-Url: https://codereview.chromium.org/2487353002
Cr-Commit-Position: refs/heads/master@{#431777}

chrome/android/java/res/xml/file_paths.xml

@@ -9,6 +9,7 @@
 <paths xmlns:android="http://schemas.android.com/apk/res/android">
     <files-path name="images" path="images/"/>
     <cache-path name="cache" path="net-export/"/>
+    <cache-path name="webapk" path="webapks/" />
 
     <!-- Note(twellington): This path is included to facilitate creating
          content:// URIs for downloads. This may no longer work if/when users

chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkInstaller.java

@@ -4,18 +4,21 @@
 
 package org.chromium.chrome.browser.webapps;
 
-import android.content.ActivityNotFoundException;
+import android.content.Context;
 import android.content.Intent;
 import android.content.pm.PackageManager;
 import android.net.Uri;
+import android.os.Build;
 import android.os.Looper;
 
 import org.chromium.base.ApplicationState;
 import org.chromium.base.ApplicationStatus;
+import org.chromium.base.ContentUriUtils;
 import org.chromium.base.ContextUtils;
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.chrome.browser.ShortcutHelper;
 import org.chromium.chrome.browser.banners.InstallerDelegate;
+import org.chromium.chrome.browser.util.IntentUtils;
 
 import java.io.File;
 
@@ -87,16 +90,24 @@ private boolean installAsyncAndMonitorInstallationFromNative(
      * @param filePath File to install.
      */
     private boolean installDownloadedWebApk(String filePath) {
-        Intent intent = new Intent(Intent.ACTION_VIEW);
-        Uri fileUri = Uri.fromFile(new File(filePath));
-        intent.setDataAndType(fileUri, "application/vnd.android.package-archive");
-        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
-        try {
-            ContextUtils.getApplicationContext().startActivity(intent);
-        } catch (ActivityNotFoundException e) {
-            return false;
+        // TODO(pkotwicz|hanxi): For Chrome Stable figure out a different way of installing
+        // WebAPKs which does not involve enabling "installation from Unsigned Sources".
+        Context context = ContextUtils.getApplicationContext();
+        Intent intent;
+        File pathToInstall = new File(filePath);
+
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.N) {
+            intent = new Intent(Intent.ACTION_VIEW);
+            Uri fileUri = Uri.fromFile(pathToInstall);
+            intent.setDataAndType(fileUri, "application/vnd.android.package-archive");
+            intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
+        } else {
+            Uri source = ContentUriUtils.getContentUriFromFile(context, pathToInstall);
+            intent = new Intent(Intent.ACTION_INSTALL_PACKAGE);
+            intent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
+            intent.setData(source);
         }
-        return true;
+        return IntentUtils.safeStartActivity(context, intent);
     }
 
     private InstallerDelegate.Observer createInstallerDelegateObserver() {

chrome/browser/android/webapk/webapk_installer.cc

@@ -397,7 +397,8 @@ void WebApkInstaller::OnCreatedSubDirAndSetPermissions(
     return;
   }
 
-  DownloadWebApk(output_dir.AppendASCII(webapk_package_), download_url, true);
+  DownloadWebApk(output_dir.AppendASCII(webapk_package_ + ".apk"),
+                 download_url, true);
 }
 
 void WebApkInstaller::DownloadWebApk(const base::FilePath& output_path,