Initial CL for talking to the WebAPK server to generate WebAPK

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

Index: chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkInstallerBridge.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkInstallerBridge.java b/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkInstallerBridge.java
new file mode 100644
index 0000000000000000000000000000000000000000..396b98522487e99f3ebac79d2ee02c3e459b40a2
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkInstallerBridge.java
@@ -0,0 +1,38 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser.webapps;
+
+import android.content.Context;
+
+import org.chromium.base.ContextUtils;
+import org.chromium.base.annotations.CalledByNative;
+import org.chromium.chrome.browser.ChromeApplication;
+
+/**
+ * Java counterpart to webapk_installer.h

[gone, 2016/07/29 21:20:28]

It's weird that you have a webapk_installer.h that hooks to a
WebApkInstallerBridge.java but you also have a WebApkInstaller.java that doesn't
actually have a native side.  Introduces more confusion than it really should. 
Why the difference?

[pkotwicz, 2016/08/02 04:09:37]

The Java WebApkInstaller implements the calls to the private Google Play Api (or
it will in the future)

chrome_apk uses WebApkInstallerImpl
chrome_public_apk does not use a WebApkInstaller at all

I can merge WebApkInstaller and WebApkInstallerBridge if you want. That would
make WebApkInstaller an abstract class and no longer an interface. Do you prefer
this?

[gone, 2016/08/03 19:03:20]

Yeah.  Thought you'd already done this for the latest patch but was mistaken. 
It makes tracking JNI calls a lot easier.

+ * Contains functionality to install WebAPKs.
+ */
+public class WebApkInstallerBridge {
+    // Prevent instantiation.
+    private WebApkInstallerBridge() {}
+
+    /**
+     * Installs a WebAPK.
+     * @param filePath File to install.
+     * @param packageName Package name to install WebAPK at.
+     * @return True if the install was started. A "true" return value does not guarantee that the
+     * install succeeds.
+     */
+    @CalledByNative
+    static boolean installAsync(String filePath, String packageName) {
+        Context context = ContextUtils.getApplicationContext();
+        WebApkInstaller apkInstaller = ((ChromeApplication) context).createWebApkInstaller();
+        if (apkInstaller == null) {
+            return false;
+        }
+        apkInstaller.installAsync(filePath, packageName);
+        return true;
+    }
+}