Add metrics to track Google Play install WebAPK failures.

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

Index: chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkInstaller.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkInstaller.java b/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkInstaller.java
index 5523f9283e1794f30c787d7516d0d98bb8c48d8f..e981b0b474f57ebd9173543776a1352682d5176a 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkInstaller.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkInstaller.java
@@ -20,6 +20,7 @@ import org.chromium.base.annotations.CalledByNative;
 import org.chromium.chrome.browser.AppHooks;
 import org.chromium.chrome.browser.ShortcutHelper;
 import org.chromium.chrome.browser.banners.InstallerDelegate;
+import org.chromium.chrome.browser.metrics.WebApkUma;
 import org.chromium.chrome.browser.util.IntentUtils;
 
 import java.io.File;
@@ -109,6 +110,8 @@ public class WebApkInstaller {
             String packageName, int version, String title, String token, String url) {
         if (mGooglePlayWebApkInstallDelegate == null) {
             notify(WebApkInstallResult.FAILURE);
+            WebApkUma.recordGooglePlayIntallResult(

[dominickn, 2017/03/22 00:15:22]

Should this conditional be moved after the isWebApkInstalled check? I'm thinking
of cases where you've managed to get a WebAPK installed, but then you trigger
another install and your Play Services isn't available. Seems like a rare case
but we may as well account for it if there are no side effects.

[Xi Han, 2017/03/22 17:32:36]

It makes sense to me. Yes, we shouldn't records anything if the WebAPK has been
installed. Moved.

+                    WebApkUma.GOOGLE_PLAY_INSTALL_FAILED_NO_DELEGATE);
             return;
         }